Selected abstracts from the North American Veterinary Dermatology Forum, 18–22 April, Lihue, Kauai, Hawaii, USA


Screening of healthy cats and cats with inflammatory skin disease for colonization of the skin by methicillin-resistant coagulase- positive staphylococci and Staphylococcus schleiferi subspecies schleiferi

J. L. ABRAHAM*, D. O. MORRIS*, G. C. GRIFFETH*, F. S. SHOFER* and S. C. RANKIN†
*Department of Clinical Studies, University of Pennsylvania School of Veterinary Medicine, and †Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA

We recently reported methicillin resistance (MR) rates of 23% for Staphylococcus aureus (MRSA), 5% for Staphylococcus intermedius (MRSI), and 37.5% for Staphylococcus schleiferi (MRSS) from feline patients cultured in our hospital. We hypothesized that these rates were reflective of referral and clinician-selection biases, and that MR staphylococcal carriage rates in less-biased feline populations are significantly lower. Fifty healthy cats and 48 cats with inflammatory skin disease (eosinophilic plaques/ulcers/granulomas, miliary dermatitis, self-inflicted alopecia, nonlesional pruritus, or inflammatory otitis) were swabbed for bacterial culture/susceptibility testing from five staphylococcal carriage sites: nasal mucosa, oral mucosa, forehead hair/skin, groin, and anal ring. Lesions were present inconsistently in sampled sites. Morphological identification, Gram's staining, catalase and coagulase testing, and biochemical speciation were performed. Latex agglutination testing for penicillin-binding protein 2a (PBP2a) and pulsed-field gel electrophoresis (PFGE) were performed on all MR isolates. mecA gene polymerase chain reaction was performed on MRSI and MRSS isolates. Sccmec typing was performed on MRSA isolates. The following staphylococci were isolated from 24 of 48 affected cats: S. aureus (14/24, 58%), S. intermedius (11/24, 46%), coagulase-negative S. schleiferi (1/24, 4%), and S. hyicus (1/24, 4%). MR rates were 7, 0, 100, and 0%, respectively. The following staphylococci were isolated from 17/50 healthy cats: S. aureus (10/17, 59%), S. intermedius (11/17, 65%), and coagulase-positive S. schleiferi (1/17, 6%). MR rates were 20, 18, and 0%, respectively. There was no significant difference in staphylococcal isolation or MR between groups. While present, MR staphylococci were significantly less common in these populations than reported previously.

This study was funded by the Dermatologic Research Endowment, University of Pennsylvania.

The effect of otic vehicle and concentration of dexamethasone on liver and adrenal function in healthy dogs

J. S. ANIYA and C. E. GRIFFIN
Animal Allergy Specialists, San Diego, California, USA

Dexamethasone in 0.1% propylene glycol vehicle has been shown to cause adrenal suppression and increased liver enzyme activities. The objectives of this study were to determine if these effects are concentration or vehicle dependent. Twenty-one privately owned normal small breed dogs were included in this double-blinded study. Chemistry panels and adrenocorticotrophic hormone (ACTH) stimulation tests were performed on days 0 and 15. Dogs were randomly assigned treatment with dexamethasone 0.01% in saline, 0.1% in saline, or 0.1% in a commercial preparation (Tresaderm®: Merial, Duluth, GA, USA) in each ear twice daily for 2 weeks. Nineteen dogs completed the study. Statistical analysis was performed using splus® (INSIGHTFUL, Seattle, WA, USA). Chi-squared pairwise comparisons found no significant differences between the three treatment groups at baseline. Kruskal–Wallis test for equivalence of means showed that significant difference existed in ACTH stimulation tests post-treatment between Tresaderm® and dexamethasone 0.01% in saline (P = 0.006), as well as dexamethasone 0.1% in saline and dexamethasone 0.01% in saline (P = 0.04). Tresaderm® and dexamethasone 0.1% in saline were equivalent (P = 0.08). In conclusion, veterinarians who formulate dexamethasone 0.1% otic solutions should be cognizant of potential adrenal suppression and increased liver enzyme activities in small breed dogs similar to that seen with Tresaderm®. Dexamethasone at 0.01% did not cause adrenal suppression in this study.

This study was self-funded with Cortrosyn® generously provided by Amphastar Pharmaceuticals, Inc.

Determination of threshold concentrations of multiple allergenic extracts for equine intradermal testing using normal horses in three seasons

C. BAXTER and L. VOGELNEST
University Veterinary Centres, University of Sydney, NSW, Australia

Forty-one normal horses were evaluated for reactivity to intradermally injected aqueous allergens to determine allergen threshold concentrations, with potential relevance to equine intradermal testing (IDT). Horses were tested three times for over 1 year to assess seasonal variation in reactivity, using three to five serial dilutions of 27 allergens each time. Injection sites were evaluated after 15 min, 1 h, 4 h and 24 h. The highest allergen concentration at which < 10% of horses demonstrated positive reactivity (subjective score of = 2, scale of 0–4) at 15 min was considered the threshold concentration (TC). The TC was determined for nine pollens (2000 to > 6000 pnu mL−1), four moulds (4000 to > 6000 pnu mL−1), insects (ant, horse fly 125 pnu mL−1; house fly, cockroach 250 pnu mL−1; moth 60 pnu mL−1; mosquito 1000 pnu mL−1; Culicoides nebeculosis 1 : 5000 w/v) and three to four storage mites (1 : 10 000 w/v). The TC was not determined due to excessive reactivity at the lowest concentrations tested for dust mites (Dermatophagoides farinae [< 1 : 12 000 w/v], Dermatophagoides pteronyssinus [< 1 : 30 000 w/v]) and Acarus siro (< 1 : 10 000 w/v). Minor variation in the TC for specific allergens occurred in different seasons. Progressive sensitization with repeat testing occurred for grain mill dust mix. Positive reactivity at 1 h and 4 h occurred in > 10% of horses for nine of 19 allergens (pollens, mosquito, storage mites) at their determined TC. Positive reactivity was rare at 24 h. This study in normal horses suggests that appropriate testing concentrations of allergens for equine IDT in atopic horses may be  1000 pnu mL−1 for pollens and moulds, 60–250 pnu mL−1 for most insects and < 1 : 12 000 w/v for dust mites; and that late phase reactions at 1–4 h may be insignificant.

This study was supported by research grants from the American Academy of Veterinary Dermatology, the Dermatology Chapter of the Australian College of Veterinary Scientists and a College Research Grant from the Australian College of Veterinary Scientists. Dr Baxter's residency program was sponsored by Virbac, Australia (Pty, Ltd).

Ectoparasites of Western barred bandicoots

M. D. BENNETT, L. WOOLFORD, A. J. O’HARA, P. K. NICHOLLS, K. WARREN and R. P. HOBBS
School of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, Western Australia, Australia

Western barred bandicoots (Perameles bougainville) from five Western Australian colonies were examined during 2006. Bandicoots were trapped or netted, then examined under isoflurane (Isorrane: Baxter Healthcare, Old Toongabbie, NSW, Australia) general anaesthesia. Fleas, ticks and larval trombiculid mites (chiggers) were collected from bandicoots and their handling bags and preserved in ethanol. Chiggers were mounted and cleared in Hoyer's medium. Fleas were boiled in potassium hydroxide, dehydrated through graded alcohols, cleared in methyl salicylate and mounted with Canada balsam. Ticks were identified using a dissecting microscope. Schoutedenichia emphyla chiggers were found on periscrotal, peripouch and aural skin in many P. bougainville from Dryandra. The ticks Haemaphysalis humerosa and H. ratti were collected from Bernier and Dorre Islands. In all, four flea species have been identified on P. bougainville. Echidnophaga gallinacea and Pygiopsylla tunneyi were common at Heirisson Prong and the Islands colonies, respectively. Xenopsylla vs. vexabilis was occasionally identified on bandicoots from Bernier Island and Heirisson Prong. Leptopsylla segnis and P. tunneyi were found on a bandicoot from Kanyana. No Austrochirus dorreensis (a fur mite) or Haemaphysalis lagostrophi were collected in 2006, despite previous literature reports. Apart from localized dermatitis with chigger infestation and mild blood loss from tick and flea attachment, the significance of ectoparasitism in P. bougainville remains unresolved. The potential role of these ectoparasites as disease vectors is under current investigation. This is the first report of S. emphyla, E. gallinacea, P. tunneyi, Xenopsylla vs. vexabilis and L. segnis in P. bougainville.

This study was conducted in partnership with Murdoch University and the Western Australian Department of Environment and Conservation and supported by an Australian Research Council linkage grant LP0455050.

Using in situ hybridization to detect a putative novel papillomavirus in biopsies from Western barred bandicoots (Perameles bougainville)

M. D. BENNETT, L. WOOLFORD, A. J. O’HARA, K. WARREN and P. K. NICHOLLS
School of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, Western Australia, Australia

A putative novel papillomavirus has been implicated in a debilitating papillomatosis–carcinomatosis syndrome affecting endangered Western barred bandicoots (Perameles bougainville). Multiply-primed rolling circle amplification was employed to amplify circular DNA from lesional tissue. This was subsequently used to deduce viral genetic sequences. DNA probes were generated for the L1, L2 (major and minor capsid proteins) and large T-antigen-like (putative oncoprotein) open reading frames. A genomic probe was also constructed from the entire viral genome, randomly cut into fragments. These probes were labelled by nick translation with digoxigenin and annealed probes were detected using antidigoxigenin alkaline phosphatase-conjugated F(ab)2 fragments and visualized with exposure to precipitating BM Purple alkaline phosphatase substrate solution (all reagents for in situ hybridization: Roche Diagnostics, Indianapolis, IN, USA). Endogenous alkaline phosphatase activity, which was especially prominent in apocrine sweat gland tissue, was blocked with levamisole. There was positive nuclear staining of keratinocytes and sebocytes in lesional biopsies from wart-affected Western barred bandicoots sampled between 2000 and 2006 for all DNA probes tested. Overfixation, freezing and autolysis all reduced the sensitivity and specificity of this technique; however, with optimally fixed, well-preserved tissue samples, positive staining was obvious and reliable. These results confirm that genetic sequences from a putative novel papillomavirus are situated within the histological lesions of the Western barred bandicoot papillomatosis–carcinomatosis syndrome, providing further evidence to support the hypothesis that this syndrome has a viral aetiology.

This study was conducted in partnership with Murdoch University and the Western Australian Department of Environment and Conservation and supported by an Australian Research Council linkage grant LP0455050.

Survey of the MDR1 gene for heterozygous mutations in dogs displaying subchronic toxicity signs to systemic macrocyclic lactones following treatment regimen for generalized demodicosis

S. BISSONNETTE*, M. PARADIS*, I. DANEAU† and D. SILVERSIDES†
*Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Montreal, St-Hyacinthe, Quebec, Canada, and †Centre de Recherche en Reproduction Animale, Faculty of Veterinary Medicine, University of Montreal, St-Hyacinthe, Quebec, Canada

P-glycoprotein (P-gp), encoded by the multidrug resistance gene (MDR1), is an integral component of the blood brain barrier and is crucial in limiting drug uptake into the central nervous system. Altered expression or function of P-gp, as seen in dogs of the collie lineage with a homozygous mutation of the MDR1 (mdr1–1Δ/mdr1–1Δ), produces a potentially fatal neurotoxicosis, especially following administration of systemic macrocyclic lactones (SML). Occasionally, dogs not related to the collie breed experience subchronic toxicity signs when receiving SML as treatment for generalized demodicosis. The hypothesis tested in this study was that these dogs could be carriers for MDR1 mutation (mdr1–1Δ/MDR1, heterozygous mutant), which could result in decreased P-gp activity and subsequent neurotoxicosis. Cheek swabs were collected from 27 dogs of various breeds with generalized demodicosis that had shown subchronic toxicity signs (4 days to 5 weeks) following daily oral administration of ivermectin (n = 24) or other SML (n = 4). Eight included dogs did receive other P-gp substrates (confirmed or putative) systemically (e.g. ketoconazole, cyclosporine) concurrently. After DNA extraction, the relevant portion of the MDR1 gene was amplified by polymerase chain reaction. Twenty-six dogs were homozygously normal (MDR1/MDR1) and one dog (Labrador cross) was heterozygous (mdr1–1Δ/MDR1) for the reported mutation. Therefore, with the exception of one dog, the neurotoxicity signs observed could not be attributed to that mutation. Some possible explanations for the adverse reactions include pharmacological interactions (administration of SML with drugs that are P-gp substrates or inhibitors), another mutation, or phenomena unrelated to the SML–P–gp interaction.

This study was supported by a research grant from the Canadian Academy of Veterinary Dermatology.

Case report – telogen effluvium in a STRAY CAT after neutering surgery

D. BOESCH*, S. BETTENAY† and C. S. NETT*
*Kleintierklinik Rigiplatz, Cham, Switzerland, and †Laboklin GmbH, Bad Kissingen, Germany

This case report describes clinical and histopathological findings, which are compatible with a diagnosis of telogen effluvium in an approximately six-year-old stray female cat. Five weeks prior to the onset of extensive nonpruritic hair loss, the cat had been rescued from the street in an apparently normal physical condition and undergone neutering surgery. At the dermatological examination, generalized, non-inflammatory, nonpruritic shedding was noted on the head, trunk and legs. Hairs were easily epilated and shorter regrowing hairs were visible. A complete blood count, serum biochemistry, skin scrapings and a fungal culture were unrevealing. The trichogram of shed hairs showed all characteristics of telogen, whereas plucked regrowing hairs showed anagen features. Histopathology was consistent with telogen effluvium with superficial follicles in the telogen phase, with prominent infundibular keratin, and a synchronous line of anagen follicles underneath it. No treatment was applied and 2 months later, at the revisit, the coat was fully regrown. Telogen effluvium due to immediate anagen release is a rare generalized alopecia seen in dogs and cats 1 to 4 months after severe metabolic stress such as high fever, pregnancy, lactation, anaesthesia, surgery or shock leading to an abrupt cessation of the normal hair cycle and a synchronous premature entry of many follicles into the telogen phase. Clinically, this causes nonpruritic progressive hair loss without any cutaneous abnormalities. Full recovery is usually seen without any therapy. To the authors’ knowledge, this is the first description of the clinical and histopathological features of telogen effluvium in a cat.

Evaluation of phytosphingosine-containing shampoo and microemulsion spray in the clinical control of allergic dermatoses in dogs: preliminary results of a multicentre study

P. BOURDEAU*, V. BRUET* and C. GREMILLET†
*Dermatology/Parasitology/Mycology, Department of Clinical Sciences, École Nationale Vétérinaire, Nantes, France, and †Laboratoire SOGEVAL, Laval, France

The aim of this study was to evaluate the clinical efficacy of phytosphingosine (PS)-containing shampoo and spray in allergic dogs. An antipruritic shampoo (Allermyl) was used as positive control. This study was multicentre, randomized and blinded (groups I–II). Inclusion criteria were: (i) pruritus ( 3 on scale of 6); (ii) diagnosis of canine atopic dermatitis (Willemse's criteria) or flea allergy; and (iii) flea control started in  3 weeks before trial. Exclusions criteria were: (i) recent corticosteroids, antihistamines, essential fatty acids, food trial; and (ii) ectoparasites or skin infections. On day 0, clinical signs and pruritus were scored. CADESI was used to score clinical signs. Dogs were placed in three groups: I (PS shampoo), II (Allermyl), and III (PS shampoo/PS microemulsion spray). Groups I and II were shampooed (days 1-4-7-10-13-16-19), and sprays replaced the last four shampoos in group III. Dogs were evaluated on day 10 and day 2O, and scores were compared. Friedman, Kruskal–Wallis test was used for statistical evaluation of pruritus scores and anova for CADESI scores. Forty-seven dogs were included in the trial. CADESI decreased by 40, 45.9 and 45. 9% and pruritus by 23.4, 22.7 and 29.8% for groups I, II and III, respectively. Changes were significant for the day 0–10 period, but not between days 10–20 or between groups. Products were well tolerated. These preliminary results suggest that PS shampoos and sprays may be beneficial in the topical management of allergic skin conditions in dogs and that sprays may be an option to replace shampoos.

Study funded through a grant from Sogeval Laboratories, Laval, France

Screening of skin and mucosal staphylococcal carriage sites in normal and feather-damaging psittacines

J. A. BRISCOE*, D. O. MORRIS*, S. C. RANKIN†, K. O'SHEA†, F. SHOFER* and K. L. ROSENTHAL*
*Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, and †Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA

It is assumed that staphylococci are commensal flora of psittacine skin, and bacterial dermatitis has been implicated in the pathogenesis of feather-damaging behaviour (FDB). The purpose of this study was to evaluate staphylococcal carriage sites in a population of normal and feather-damaging psittacines. We hypothesized that there would be no difference in the staphylococcal population between these two groups, and that bacterial dermatitis is not part of the aetiology for FDB. Samples from 180 psittacines (54 FDB birds, 126 non-FDB birds) were obtained from two mucosal carriage sites – the choana and cloaca – as well as from the uropygial gland. Morphological identification, Gram stains, catalase tests, and biochemical speciation were performed. Latex agglutination testing for penicillin-binding protein 2a (PBP), PCR for the mecA gene, and pulsed-field gel electrophoresis (PFGE) were performed on all coagulase-positive isolates. A bird was classified as ‘positive’ if one or more sample sites were positive for one or more staphylococcal species. There was no difference between the two study groups (P = 0.871), nor were there differences in frequency of methicillin resistance in staphylococci isolated from the two groups (P = 0.642). Although the prevalence of S. intermedius was significantly higher in FDB birds (P = 0.009), these birds were housed in a common facility and PFGE showed these isolates to be clonal. Our results suggest that there are no differences in the commensal staphylococcal population of FDB vs. non-FDB birds, supporting our hypothesis that staphylococci do not play a significant role in the aetiology of FDB.

This study was supported in its entirety by the American Academy of Veterinary Dermatology.

An original case of alopecia (areata) universalis with severe onychodystrophy in a horse

V. BRUET*, F. DEGORCE-RUBIALES† and P. BOURDEAU*
*Unit Dermatology/Parasitology/Mycology – School of Veterinary Medicine, Nantes, France, and †Laboratory of Histopathology, LAPVSO, Toulouse, France

A 22-year-old French trotter mare was presented to the dermatology Unit of École Nationale Vétérinaire de Nantes with a 9-month history of extensive non-inflammatory alopecia. Dermatological examination showed generalized and complete alopecia (except the ears and partially the axillae, groin and ventral neck areas) including mane and tail. This was associated with a progressive marked dystrophy of the four hooves. Onychogryphosis, onychoschisis, onychorrhexis with ripples and ridges without any sign of coronitis were noted. Skin and hooves lesions developed simultaneously. There was no systemic sign. Radiological examinations ruled out laminitis as a possible cause of hooves changes. Histopathological examination of biopsy samples from three sites showed a similar pattern, with lymphocytic inflammatory infiltrate affecting the hair bulbs, consistent with a diagnosis of alopecia areata. The concurrent presence of onychodystrophy and alopecia areata is very unusual in veterinary dermatology. On the opposite, in human dermatology, this association is quite common (30% of cases). Nail lesions consist of diffuse fine pitting (most common), thin and brittle nails and trachyonychia. Alopecia and nail changes may resolve spontaneously. Prognosis of alopecia areata in humans is, however, less favourable when combined with nail changes. In this case, only hooves care was done to improve the locomotion of the horse. Six months later there was no progression of the disease. To our knowledge this is the first reported case of alopecia areata universalis associated with onychodystrophy in a horse.

This work was supported by the Unite de Dermatologie Parasitologie Mycologie Unit.

Screening of skin and mucosal carriage sites for staphylococci in psittacines

J. A. BRISCOE*, D. O. MORRIS*, S. C. RANKIN†, F. SHOFER* and K. L. ROSENTHAL*
*Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA, and †Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA

It is assumed that staphylococci play a significant role in the commensal microflora of psittacines even though the normal cutaneous bacterial microflora in psittacines has not been established. Furthermore, prevalence of methicillin resistance within the staphylococcal population of psittacines has not been characterized. The purpose of this study was twofold: to survey skin and mucosal staphylococcal carriage sites of two populations of psittacines differing by geographical location and exposure to human contact; and to evaluate the isolates for methicillin resistance (MR). Samples from 180 psittacines (107 sanctuary and 73 pet birds) were obtained from two presumed mucosal carriage sites – the choana and cloaca – and from the uropygial gland, which is the only seborrheic site that exists on birds. Morphological identification, Gram stains, catalase tests, and biochemical speciation were performed. Latex agglutination testing for penicillin-binding protein 2a (PBP), PCR for the mecA gene, and pulsed-field gel electrophoresis (PFGE) were performed on all MR isolates. Staphylococcus spp. were isolated from 37 of 107 (35%) sanctuary birds and 52 of 73 (71%) pet birds (P = 0.0001). Coagulase-positive strains – most of which were S. intermedius– were statistically more common on the sanctuary birds (P = 0.0001). PFGE of the S. intermedius isolates revealed a clonal population. All MR isolates were coagulase negative, and there was no significant difference between the numbers isolated from sanctuary vs. pet birds. Our results indicate that exposure to humans may increase the likelihood of carriage of staphylococci but does not necessarily alter the MR status of the population.

This study was funded with a grant from the American Academy of Veterinary Dermatologists.

Variation in gross and histological appearance of the canine pars flaccida

L. K. COLE*, S. E. WEISBRODE† and D. D. SMEAK*
*Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA, and †Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA

The tympanic membrane is divided into the pars flaccida (PF) and pars tensa. Differences in the appearance of the PF in the dog (flat vs. bulging) have been reported anecdotally. The purpose of this study was to histologically examine the canine PF to determine if differences exist between a flat and bulging PF. We hypothesized that differences in the PF may be structural or due to an increased pressure in the middle ear. Four adult canine cadavers were used (two had bilateral bulging PF, two had bilateral flat PF). The ear specimens were fixed in 10% buffered neutral formalin, decalcified, routinely processed and stained with haematoxylin and eosin, toluidine blue (staining for mast cells), and Verhoeff–Van Gieson (staining for elastic fibres). One blinded investigator evaluated each PF histologically. Seven ears (3 with bulging PF, 4 with flat PF) were evaluated in the study. The PF was identified in all seven ears. No histological differences were identified that distinguished a bulging PF from a flat PF. Six ears were evaluated for the presence of mast cells and elastic fibres. Less than one mast cell per ×40 field was identified in the PF in five of six ears. No elastic fibres were identified in any of the six PF. Based on the results of this study, it appears unlikely that there is a structural difference that accounts for a bulging PF. Therefore, there may be increased middle ear pressure in dogs with a bulging PF.

This study was self-funded.

Oral lesions in a case of sterile granuloma and pyogranuloma syndrome

S. F. DIAZ and S. GILBERT
NYC Veterinary Specialists, New York, NY, USA

Sterile granuloma and pyogranuloma syndrome is described as a heterogeneous group of nodular skin lesions with the inflammatory reaction being histiocytic in nature. The most common clinical signs in the dog consist of multiple, firm, well-demarcated, variable-alopecic dermal nodules or plaques. Lesions most commonly affect the head, pinnae and periorbital skin, but are also seen on the neck, trunk and extremities. We report a case of multifocal pyogranulomatous dermatitis and glossitis in a 2-year-old, female spayed dachshund. Multiple nodular lesions varying from 2 mm to 2 cm in diameter were present on the tongue, trunk and extremities. The largest skin lesions were ulcerated and producing a clear viscous fluid. Multiple small (2–3 mm diameter) lesions were present on the tongue. Lingual and skin lesions showed similar histopathological characteristics, consisting of variable-sized, nodular foci of pyogranulomatous inflammation. The skin lesions were present in the dermis and often extending to the panniculus, while the tongue lesions were present in mucosal connective tissue, and within areas of muscle. Fresh tissue biopsies were submitted for aerobic and anaerobic bacterial cultures, fungal cultures and mycobacterial polymerase chain reaction. All results were negative. A diagnosis of sterile granuloma and pyogranuloma syndrome was made. The lesions responded well to oral prednisone therapy. To the authors’ knowledge, cases of sterile granuloma and pyogranuloma syndrome affecting the tongue have not been reported previously.

Multiple comedones and follicular cysts in the interdigital and elbow skin causing furunculosis and draining tracts in dogs: a case series

D. D. DUCLOS* and A. M. HARGIS†
*Animal Skin and Allergy Clinic, Lynnwood, Washington, USA, and †DermatoDiagnostics, Edmonds, Washington; Phoenix Central Laboratory, Everett, Washington; and Department of Comparative Medicine, School of Medicine, University of Washington, Seattle, Washington, USA

The objective of this study was to document the presence of comedones and follicular cysts of interdigital and elbow skin as an underlying cause of recurrent dermatitis in a group of dogs, and to describe the use of carbon dioxide laser to surgically remove lesions. Dogs included in this study (i) had recurrent lameness, pain, nodules, or draining sinuses in interdigital or elbow skin; (ii) failed to respond to antibiotic therapy; (iii) had negative skin scrapings for Demodex mites and negative hair examinations for dermatophytes; and (iv) were nonpruritic. Twenty-eight of 32 dogs had interdigital lesions and four had elbow lesions. Seventeen dogs had biopsy samples collected for histopathology and 31 had laser surgery. Fourteen of 28 dogs with interdigital lesions were Labrador retrievers. Clinical lesions included alopecia, callus, and comedone formation in palmar interdigital or elbow skin and a draining sinus in dorsal interdigital skin or skin at the edge of the elbow callus. Histological lesions included hyperkeratosis, acanthosis, comedone and follicular cyst formation, furunculosis, draining sinuses, and scarring. Laser surgery allowed identification and removal of multiple layers of cysts, tracking and removal of sinuses, and removal of adjacent hair follicles. Post-surgical follow up ranged from 6 months to 7.5 years (average 2.7 years). Laser surgical removal of affected skin and adjacent hair follicles resulted in resolution of lameness, pain, nodules, or draining sinuses 28 dogs. The remaining four dogs improved from having almost persistent lameness, nodules, or draining sinuses, to having one to two episodes per year.

The clinical and histopathological effects of prednisone on acute radiation dermatitis in dogs: a placebo-controlled, randomized, double-blind prospective clinical trial

A. K. FLYNN*, D. M. LURIE*, J. WARD†, D. LEWIS* and R. MARSELLA*
*Department of Clinical Sciences, School of Veterinary Medicine, University of Florida, Gainesville, Florida, USA, and †Department of Infectious Diseases and Pathology, School of Veterinary Medicine, University of Florida, Gainesville, Florida, USA

The purpose of this study was to evaluate the clinical and histopathological effects of prednisone on acute radiation- induced dermatitis (ARID) in dogs with excised soft tissue sarcomas and mast cell tumours on one extremity treated with fractionated irradiation. This prospective clinical trial was double blinded, randomized and placebo controlled. Twenty-two, otherwise healthy companion dogs completed the study. Three dogs were excluded from complete histopathology analysis because the owner declined one (1 dog) or both (2 dogs) biopsies. The study duration for each dog was 36 days from the start of radiation therapy (RT) to the first recheck exam. Dogs were treated with either oral prednisone at 0.5 mg kg-1 or sugar pill daily. All dogs received 48 Gray of fractionated, standardized RT, beginning 2 weeks after tumour excision. Veterinary radiation therapy oncology group Acute Morbidity Scores (AMS), Veterinary radiation Cutaneous Toxicity Extent and Severity (CUTES) scores, digital images, and impression cytology were done on days: 1, 8, 15, 22 and 36. Four millimetres punch biopsies from days 15 and 36 were scored by two examiners, blind to biopsy identity. A mixed model autoregressive with order one covariance matrix and a 95% confidence interval was used to compare scores between groups. Spearman rho correlation was used to measure strength of association between clinical and histopathology scores. There was no significant difference in CUTES or AMS scores between groups. There was a strong correlation between clinical and histopathology scores. In conclusion, prednisone did not decrease ARID severity clinically or histopathologically.

This study was sponsored by an American College of Veterinary Dermatology resident research grant and a University of Florida, College of Veterinary Medicine resident research grant.

Evaluation of persistence of terbinafine in the hair of normal cats after 14 days of daily therapy

A. L. FOUST*, R. MARSELLA*, L. H. AKUCEWICH*, G. KUNKLE*, A. STERN*, S. MOATTARI†‡ and N. J. SZABO†‡
*Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA, †Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, Florida, USA, and ‡Analytical Toxicology Core Laboratory, CEHT, University of Florida, Gainesville, Florida, USA

This study determined residual levels of terbinafine in cat hair after 14 days of treatment. Ten clinically normal cats were administered terbinafine (Lamisil®, Novartis, Auckland, New Zealand) orally at a daily dose of 34–45.7 mg kg−1 for 14 days. Areas of 15 cm2 were shaved on the thorax at day 0 and weekly for 8 weeks following the administration of the drug. The hair samples were analysed by high-pressure liquid chromatography to determine the persistence of terbinafine over time.

The growth curve was fitted by using one-compartment pharmacokinetic model with repeated measure. The mean terbinafine level in hair was 2.30 ng mg−1 after 14 days of therapy, or 75 times the mean inhibitory concentration for 90% (MIC90) of the most common veterinary dermatophytes. With a 99% confidence interval, evaluated by using Scheffe's adjustment, the level of terbinafine remained in the hair is  0.03 ng mg−1 for approximately 5.3 weeks. Slight deviations in blood parameters were not attributed to terbinafine.

Four cats experienced vomiting during the terbinafine treatment: two of these cats also experienced intense facial pruritus followed by a macular to papular skin reaction 7–14 days after the discontinuation of terbinafine.

In summary, terbinafine persists in hair at levels above the MIC for several weeks after stopping medication, even after short-term therapy (14 days). These results suggest that pulse therapy of terbinafine should be further researched and potentially considered as a treatment for feline dermatophytosis, an approach that would decrease treatment duration while maintaining effectiveness.

This study was supported by the University of Florida, College of Veterinary Medicine, Resident Intramural Grant and the American College of Veterinary Dermatology Research Award.

Oestrogen receptor antagonist and hair regrowth in dogs with hair cycle arrest (alopecia X)

L. A. FRANK
Department of Small Animal Clinical Sciences, University of Tennessee, Knoxville, TN, USA

An oestrogen receptor pathway that regulates the telogen–anagen hair follicle transition in mice has been described. The purpose of this study was to investigate whether fulvestrant, a pure oestrogen receptor antagonist, would cause hair regrowth in Pomeranian dogs with hair cycle arrest (alopecia X). Eleven Pomeranian dogs with hair cycle arrest were randomly assigned to receive two intramuscular injections of either 10 mg kg−1 fulvestrant (n = 6) or an equal volume of saline (n = 5) 1 month apart. Complete blood count, chemistry panel, and urinalysis were monitored prior to the first injection and monthly for 2 months. Dogs were evaluated each month for degree of hair growth, percentage of body affected, and quality of new hair growth. Three control dogs received fulvestrant after the completion of the study. In addition, one control dog and one treatment dog received two subcutaneous injections of 20 mg kg−1 fulvestrant 1 month apart. No dogs that received 10 mg kg−1 fulvestrant had any evidence of hair regrowth. The control dog that received 20 mg kg−1 fulvestrant had substantial hair regrowth 1 month after the first injection. No adverse effects from the treatment were noted. Fulvestrant does not appear to be a feasible treatment for dogs with hair cycle arrest (alopecia X) when administered intramuscularly at 10 mg kg−1. A higher dose of fulvestrant requires more investigation but may be cost-prohibitive.

This project was funded by the American Kennel Club Canine Health Foundation.

The evaluation of the efficacy of commercially available veterinary diets recommended for dogs with atopic dermatitis

K. GLOS and R. S. MUELLER
Medizinische Kleintierklinik, Ludwig Maximilian University, Munich, Bavaria, Germany

The classical treatments for dogs with atopic dermatitis have traditionally been oral antipruritic drugs, allergen-specific immunotherapy and topical therapy. Forty-two dogs with atopic dermatitis were included in this multicentred, double-blinded, randomised study to evaluate clinical response to an 8-week period of feeding one of three veterinary diets marketed for dogs with atopic dermatitis (diet A was a selected protein diet with fish and rice, diet B was Eukanuba Veterinary Diets Dermatosis FP, diet C was a hydrolysed diet) or a general diet widely distributed in supermarkets (diet D). Atopic dermatitis was diagnosed using Willemse's criteria and through the exclusion of differential diagnoses. Thirteen dogs were assigned to diet A, 11 to diet B (Eukanuba Dermatosis FP), 9 to diet C and 9 to diet D. Eleven dogs with diet A (85%), nine dogs with diet B (82%), seven dogs with diet C (78%) and seven dogs with diet D (78%) had previously been through a hypoallergenic dietary trial. Flea and tick control using a monthly fipronil spot-on was administered for a minimum of 4 weeks prior to and including the study period. Evaluations were made monthly. These included lesional scores, using an established scoring system (CADESI = Canine Atopic Dermatitis Extent and Severity Index) and owner evaluated patient – pruritus levels using a visual analogue scale. After 8 weeks on the new foods, the CADESI and pruritus scores of dogs assigned to diet B were significantly decreased (P = 0.0404 and P = 0.0080), whereas dogs assigned to diet A only showed significantly less pruritus (P = 0.0424). No significant changes were detected with diets C and D. Based on the results of this study, changing the diet of dogs with atopic dermatitis may be a useful adjunctive therapeutic measure in addition to conventional therapies.

The authors are grateful to Drs Monika Linek, Christine Löwenstein, Nina Gerhards, Jürgen and Dorothe Schmid for participating in that multicentred study and to P & G Pet Care for financing the project.

Screening of healthy dogs and dogs with inflammatory skin disease for surface colonization by methicillin-resistant coagulase-positive staphylococci and coagulase-negative Staphylococcus schleiferi

G. C. GRIFFETH*, D. O. MORRIS*, J. L. ABRAHAM*, F. S. SHOFER* and S. C. RANKIN†
*Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, and †Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA

We have recently reported methicillin resistance (MR) rates of 40.5% for Staphylococcus aureus (MRSA), 15.9% for Staphylococcus intermedius (MRSI), and 40.3% for S. schleiferi (MRSS) cultured from dogs in our hospital. We hypothesized that these rates were reflective of referral and clinician-selection biases and that rates of colonization or infection with MR staphylococci in a less biased sample would be significantly lower. Fifty normal dogs and 59 dogs with inflammatory skin disease were swabbed for bacterial culture from five sites: nasal mucosa, oral mucosa, caudodorsal head, groin, and anal ring. Morphological identification, Gram's staining, catalase and coagulase testing, and biochemical speciation were performed. Pulsed-field gel electrophoresis and testing for penicillin-binding protein 2a were performed on all MR isolates. MecA polymerase chain reaction was performed on MRSI and MRSS isolates. Sccmec typing was performed on MRSA isolates. For the above Staphylococcus spp., 55 of 59 affected dogs and 35 of 50 normal dogs were positive at one or more sites. There was no significant difference in staphylococcal carriage or MR among sites sampled. Species identified in culture-positive affected dogs included: S. intermedius (83.6%), S. aureus (9.1%), coagulase-positive S. schleiferi (7.3%), and coagulase-negative S. schleiferi (9.1%). MR rates were 8.7, 20, 25, and 20% from these species, respectively. Species identified in culture-positive normal dogs included S. intermedius (97.1%), S. aureus (20.0%), and coagulase-positive S. schleiferi (2.9%). MR rates were 2.9, 14.3, and 0.0% in these species, respectively. While still present, MR staphylococci are significantly less common in the less biased populations screened in this study.

This study was funded by a grant from the American Kennel Club Canine Health Foundation.

Two unusual cases of auricular cartilage disease

C. E. GRIFFIN* and A. M. TRIMMER†
*Animal Dermatology Clinic, San Diego, California; and †Animal Dermatology Clinic, Las Vegas, Nevada, USA

Auricular chondritis is a rare disease mostly described in cats, with nodular to plaque lesions affecting the pinnae. Described are two cases of auricular cartilage disease each histopathologically distinct from auricular chondritis as described in the literature. A 14.5-year-old Himalayan mix breed cat presented with a 1 month history of an erythematous thickened left ear. Two years prior, the cat had chronic right otitis externa and media that was treated with a bulla osteotomy and ear canal ablation. The left external orifice and tragus had several papules and the main lesion was a firm plaque of the base of the pinna. Two biopsies from the concave surface of the pinna and tragus that included cartilage revealed moderately severe eosinophilic lymphoplasmacytic interstitial dermatitis and necrotizing chondritis. CBC, chemistry and urinalysis was normal except for eosinophilia (1512 eos µL−1[N 0–1000 µL−1]). Lesions are milder but present despite some short-term treatments 17 months later. Eosinophilia and eosinophilic infiltrates have not previously been described. The second case was a 22-week-old Labrador mix with a 2-week history of bumps on ears. The lesions did not affect the dog. Both pinna had multiple papules that when punctured initially oozed a clear serous fluid followed by haemorrhage. Histopathology revealed cell poor central cartilage necrosis with the cartilage appearing washed out and necrotic. Haemorrhage was apparent but no other evidence of vasculitis. Similar lesions have not been previously reported. Therapy was ineffective and lesions still persist 32 months later.

Development, optimization and validation of a scale for the assessment of pruritus in dogs

P. B. HILL, P. LAU and J. RYBNICEK
Division of Companion Animal Studies, Department of Clinical Veterinary Science, University of Bristol, Bristol, UK

Assessment of pruritus is critical in dermatological history taking, both for initial diagnosis and for monitoring treatment. Various methods of assessing pruritus in the dog have been described but none have been validated. In this study, four different pruritus scales were initially assessed: a 0–5 numerical scale; a scale containing six categories of pruritic behaviours; a scale with six basic descriptors of severity; and a visual analogue scale with severity descriptions at either end. One hundred and fifteen owners were asked to grade their dog's pruritus with each of the four scales given to them in a randomized order, and asked which they thought was easiest to use, which was most accurate, and which two scales they would combine to make a superior scale. Pruritus scores from different scales were highly correlated with each other, indicating that all had merit, but owners considered the severity and behaviour scales easiest to use and the behaviour scale most accurate. The most popular combinations requested were severity and behaviour, and behaviour and visual analogue. Based on the clients’ responses, a new scale was developed that combined features of the behaviour- and severity-based scales with the visual analogue scale. When tested on 118 owners, 97% thought it was easy to use and accurate. In 32 cases, independent scores obtained by two owners were highly correlated (P < 0.0001), confirming the scale's repeatability. The new scale proved to be an easy, accurate and repeatable method for owners to determine the severity of pruritus in their dog.

This study was not funded.

Coagulase-positive staphylococci at carriage sites post-cefpodoxime therapy in dogs

A. HILLIER*, L. R. PINCHBECK†, T. BANNERMAN‡, L. K. COLE* and S. YORK‡
*Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA, †South Texas Veterinary Allergy and Dermatology, San Antonio, Texas, USA, and ‡The Ohio Department of Health, Columbus, Ohio, USA

Coagulase-positive staphylococci (CPS) may be isolated from carriage sites (CS) in dogs and these CPS are genotypically related to CPS isolated from pustules in dogs with superficial bacterial folliculitis (SBF). We hypothesized that CPS could be isolated from CS at the time of resolution of SBF following systemic antimicrobial therapy. Culture samples were collected from three CS (nasal mucosa, anal ring, axilla skin) before and after treatment, and from three pustules before treatment in 18 dogs successfully treated with cefpodoxime (Simplicef®: Pfizer, New York, NY, USA) for SBF. Isolates were identified morphologically and biochemically, pulsed-field gel electrophoresis (PFGE) was performed and PFGE patterns of isolates pre- and post-treatment were compared for genotypic (strain) relatedness. Sixteen CPS were cultured from CS in 14 of 18 dogs post-treatment. There were 13 Staphylococcus intermedius, 2 Staphylococcus schleiferi coagulans and 1 Staphylococcus aureus isolated from the anal ring (n = 10 isolates), nasal mucosa (3) and axilla skin (3) post-treatment. Of the 16 post-treatment CS isolates, seven (from 7 dogs) were indistinguishable (same strain) from pretreatment pustule isolates, three were indistinguishable from pretreatment CS isolates (3 dogs) and six were unrelated to pretreatment isolates from pustules or CS (6 dogs). In this study, CPS (S. intermedius in particular) were isolated at CS post-cefpodoxime treatment, they were most commonly found at the anal ring, and post-treatment CS isolates were the same strain as pretreatment pustule isolates in seven of 18 (39%) dogs. Persistence of pathogenic CPS at CS may be important in the pathogenesis of recurrent SBF of dogs.

This study was supported by a grant from Pfizer Animal Health.

Dermatophagoides farinae-specific IgG responses in atopic dogs undergoing allergen-specific immunotherapy with aqueous vaccines

C-C. HOU*, C. E. GRIFFIN† and P. B. HILL‡
*The Royal (Dick) School of Veterinary Studies, University of Edinburgh, UK, †Animal Dermatology Clinic, San Diego, California, USA, and ‡Division of Companion Animal Studies, Department of Clinical Veterinary Science, University of Bristol, Bristol, UK

The molecular and immunological mechanisms associated with successful allergen-specific immunotherapy (ASIT) have not been completely elucidated. The aim of this study was to characterize the changes in Dermatophagoides farinae-specific IgG in atopic dogs undergoing ASIT using aqueous vaccines. Fifteen dogs with D. farinae hypersensitivity were treated with aqueous vaccines for a minimum of 2 months following a standard protocol. Serum samples were collected before and during therapy and used to probe Western blots containing separated proteins of D. farinae. IgG responses were detected using a polyclonal goat anticanine IgG antibody and a chromogenic substrate 3,3′-diaminobenzidine (DAB). The blots were analysed using a semiquantitative digital image analysis system that evaluated the number and molecular weight of bands, as well as their intensity, which was related to IgG concentration. Prior to ASIT, all dogs showed allergen-specific IgG responses to various antigens of D. farinae. During ASIT, there was a significant increase in the total quantity of D. farinae-specific IgG antibodies to various antigens from the mite (P = 0.015). Significant increases were observed for a 98-kDa band (P = 0.015), likely to be Der f 15; bands with molecular weights between 50 and 70 kDa (P = 0.012); and bands between 30 and 45 kDa (P = 0.035). These findings provide support for the hypothesis that ASIT induces IgG blocking antibodies to allergens known to be relevant in canine atopic dermatitis.

This study was self-funded.

Cultivation and characterization of skin-derived mast cells in comparison to the bone marrow-derived mast cells in the dog

S. KAWARAI*, K. MASUDA†, K. OHMORI*, S. MATSUURA*, N. YASUDA*, M. NAGATA‡ and H. TSUJIMOTO*
*Department of Veterinary Internal Medicine, University of Tokyo, Japan, †Research Center for Allergy and Immunology, RIKEN Yokohama Institute, Kanagawa, Japan, and ‡Animal Dermatology Center, ASC, Tokyo, Japan

A purified skin-derived mast cell culture system is potentially very useful for immunological and pharmacological studies of allergic skin diseases. This study was performed to establish an efficient culture system of skin-derived cultured mast cells (skin MC) and to characterize the cells in comparison to bone marrow-derived cultured mast cells (BMCMC). Enzymatically digested skin biopsy samples were cultivated in serum-free AIM-V medium supplemented with recombinant canine stem cell factor. One to 2 months after initiation of culture, mast cells were purified using Antic-Kit antibody with magnetic beads cell-sorting system. The culture cells were composed of a uniform population showing morphology characteristic to mast cells with a round or oval nucleus and abundant toluidine blue-positive metachromatic granules. Flow cytometric analysis for surface c-Kit and FcåRIá revealed the purity of mast cells as high as 90.3 ± 6.6%. The cytoplasmic granules were shown to be positive for both of tryptase and chymase. Apparent dose-dependent degranulation was shown after incubation with high-IgE dog serum followed by anticanine IgE antibody as detected by beta-hexosaminidase assay. Skin MC had larger numbers of cytoplasmic granules with strong tryptase and chymase activity than BMCMC. Flow cytometric analysis for FcåRIá revealed stronger fluorescence intensity in BMCMC than in skin MC and the amount of IgE-mediated degranulation in BMCMC was larger than that in skin MC (P < 0.05, paired t-test). These results indicate the usefulness of the culture method employed here to obtain a pure population of canine skin MC.

Assessment of cross-reactivity among five species of house dust and storage mites based on the results of ELISA cross-inhibition

K. W. LEE*, R. E. ESCH*, R. MARSELLA†, M. N. SARIDOMICHELAKIS‡, R. FARMAKI§ and A. F. KOUTINAS§
*Greer Laboratories Inc., Lenoir, North Carolina, USA, †Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA, ‡Department of Clinical Studies, School of Veterinary Medicine, University of Thessaly, Karditsa, Greece, and §Department of Clinical Studies, Faculty of Veterinary Medicine, Aristotles University of Thessaloniki, Thessaloniki, Greece

Cross-reactivity of allergens derived from mites has long been suspected. Cross-reactivity among Dermatophagoides farinae (DF), Dermatophagoides pteronyssinus (DP), Acarus siro (AS), Tyrophagus putrescentiae (TP), and Lepidoglyphus destructor (LD) was assessed using specific IgE ELISA cross-inhibition. Serum from eight high-IgE responder beagles that were experimentally sensitized to DF, but were without prior exposure to other mite species, and 15 dogs that exhibited natural atopic dermatitis were evaluated. When the ratio of inhibiting (liquid phase) to homologous (solid phase) allergen required for 50% inhibition was  3, cross-reactivity was considered evident. Reactivity to DF, DP, and LD evident in dogs specifically sensitized to DF was completely inhibited, and specific reactivity to AS (87.5%) and TP (57.1%) in these dogs was substantially inhibited by DF antigens. In dogs exhibiting naturally occurring atopic dermatitis, DF antigens not only inhibited the DF reactivity in all of the dogs tested, these antigens inhibited 100% of reactivity to DP, 73.3% reactivity to AS and TP, and 80% or reactivity to LD. In reciprocal cross-inhibitions, DP antigens effectively reduced reactivity to DF, AS, TP, and LD in only 8.3, 23.1, 0, and 60% of the cases, respectively. The storage mites AS and TP inhibited substantial reactivity to DF and DP in 58.3–100% of reactive dogs, whereas, cross-inhibition by LD in these dogs (0–23%) was minimal. These findings demonstrate that IgE antibodies induced by DF cross-react with antigens derived from other mites and underline the importance of cross-reactivity among house dust and storage mites in atopic disease.

This study was self-funded.

The presence of pollen and house dust mite allergen-specific IgE in serum samples of 15 SPF cats and prevalence of house dust mite allergens (Dermatophagoides pteronyssinus 1, Dermatophagoides farinae 1, and mite group 2) in their microenvironment

K. E. LOFT* and K. PEDERSEN†
*Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI 48823-1314, USA, and †Aalborg Small Animal Hospital, Dk-9200 Aalborg SV, Denmark

The ability to use allergen-specific IgE to detect potential sensitization towards pollens and house dust mite allergen (HDMA) has been used extensively in humans and dogs. Literature has raised some questions as to the validity of testing for HMDA-specific IgE in cats. The purpose of this study was to examine specific-pathogen free (SPF) housed cat's serum for the presence of pollen and HDMA-specific IgE, and to examine their microenvironment for the presence of HDMA. Serum samples were collected in August 2005 from fifteen, 6-month old, intact, female, SPF cats. Samples were submitted for allergen-specific IgE testing to a HESKA partner laboratory*. The cats were caged in a basement facility with regular atmospheric airflow (no HEPA filter) and a constant temperature and relative humidity. Dust samples from the cage room were collected by vacuuming the floor 2 min m−2. The dust samples were analysed by a validated ELISA test for Dermatophagoides pteronyssinus 1 (D p1), Dermatophagoides farinae 1 (D f1), and group 2 allergens. No HDMA was detected. Two of 15 cats had positive allergen-specific IgE levels to one pollen, four of 15 were positive to two to three pollens, and one of 15 was positive for D. farinae. In conclusion, significant pollen and HMDA-specific IgE concentrations were detected in the serum samples of seven of 15 SPF housed cats, in an HDMA-free environment, with probable low pollen levels (pollen count not available). As all cats were free of any dermatological or respiratory signs at the time of sampling, the results suggest false-positive reactions in relation to any active clinical disease.

*The ELISA testing was self-funded by K. Pedersen, who is the owner of the Vet-Allergy laboratory in Denmark.

House dust mite allergens (Dermatophagoides pteronyssinus 1, Dermatophagoides farinae 1, and mite group 2) in the microenvironment of cats

K. E. LOFT and E. J. ROSSER JR
Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA

House dust mite allergens (HDMA) have been identified as one of the most common allergens in bedding materials causing allergic diseases such as human asthma and canine atopic dermatitis. The purpose of this study was to determine if HDMA could be detected in several microenvironments of cat households. From 50 cat-only households, dust samples were collected by vacuuming for 2 min m−2 from three areas, where cats slept or rested regularly, from September to October 2006. Relative humidity and temperature were measured in each household using a data logger. Each owner completed a questionnaire regarding potential factors that might influence the prevalence of house dust mites (HDM). Dust samples were analysed using an ELISA for Dermatophagoides pteronyssinus 1, Dermatophagoides farinae 1, and mite group 2 allergens. In 38 of 50 households, the HDMA levels were above 2 ng g−1 of dust for at least one of the HDMA. Using stepwise logistic regression, factors increasing HDMA included free-standing houses, number of humans in household, cats suffering from dermatological disease, longhaired cats, and age of the cat. Factors decreasing HDMA concentration in the microenvironment included forced air heating and central air-conditioning, less than 50% carpeting of the home, use of flea control, and the average temperature of the household. The sleeping/resting area of cats contains sufficiently high levels of HDMA to be a likely source of sensitization towards HDMA. This finding should lead to further determination of the role of HDM in cats suffering from atopic dermatitis or asthma.

This project was funded by Michigan State University's Companion Animal Fund.

A comparison of the diabetogenic effects of dexamethasone and prednisolone in cats

A. D. LOWE*, T. K. GRAVES*, K. L. CAMPBELL* and D. J. SCHAEFFER†
*Department of Veterinary Clinical Medicine, University of Illinois, Urbana, Illinois, USA, and †Department of Veterinary Biosciences, University of Illinois, Urbana, Illinois, USA

A potential consequence of glucocorticoid use in cats is the induction of diabetes mellitus. The diabetogenic properties of various glucocorticoids may vary. The purpose of this study was to compare the effects of prednisolone or dexamethasone on feline glucose and insulin homeostasis. Fourteen cats received either prednisolone (4.4 mg kg−1 day−1) or dexamethasone (0.55 mg kg−1 day−1) for 56 days. Serum fructosamine concentrations and urine glucose were measured on days 0, 28 and 56. Insulin sensitivity and peak serum insulin response to arginine were measured on days 0 and 56. Fructosamine concentrations, insulin sensitivity and peak insulin concentrations were compared using a multivariate repeated measures analysis of variance (systat version 11.01, Systat Inc., Richmond, CA, USA). The prevalence of glucosuria was compared using an exact test of the difference between two binomial proportions (statxact version 7, Cytel, Cambridge, MA, USA). Statistical significance was accepted at P < 0.05. Serum fructosamine concentrations increased significantly in all cats and there was a trend towards greater fructosamine concentrations in the dexamethasone-treated group on day 56. On day 56, the number of cats with glucosuria was significantly greater in the dexamethasone-treated group. Insulin sensitivity decreased significantly in all cats and there was a trend towards a greater decrease in insulin sensitivity in the dexamethasone-treated cats. Peak arginine-stimulated serum insulin concentrations were significantly higher in all cats on day 56. The mean peak insulin concentration was lower in dexamethasone-treated cats at day 56. Dexamethasone may be more diabetogenic than prednisolone in cats.

This study was supported by the University of Illinois Companion Animal Memorial Fund, the Northern Illinois Veterinary Medical Association and the Ralston Purina company.

Increased mRNA expressions of Th2 cytokines in cultured PBMCs of high-IgE beagles

S. MAEDA*, H. TSUCHIDA*, E. CREARY† and R. MARSELLA†
*Department of Veterinary Internal Medicine, Gifu University, Gifu, Japan, and †Department of Small Animal Clinical Sciences, University of Florida, Gainesville, Florida, USA

The aim of this study was to evaluate mRNA expressions of Th1 (IFN-gamma, IL-12 and IL-18) and Th2 (IL-4, IL-10 and IL-13) cytokines in peripheral blood mononuclear cells (PBMCs) of high-IgE beagles. The PBMCs were separated from six high-IgE beagles and cultured for 96 h with or without Dermatophagoides farinae (75 µg mL−1, Greer Laboratories, Lenoir, NC, USA). The cultured PBMCs were collected every 24 h during the culture period and immediately stored at −80 °C. Total RNA was isolated from the PBMCs and used for quantitative analysis of mRNA expressions using real-time PCR. No significant mRNA expressions of IFN-gamma and IL-12 were observed in any samples. Expression level of IL-10 was gradually increased overtime, however, no significant difference was found between the culture conditions (with and without D. farinae). Expressions of IL-4 and IL-13 mRNA were detected in individual samples and their levels stimulated with D. farinae were significantly higher than those of unstimulated samples. It was also found that expression level of IL-18 mRNA was gradually increased in culture without D. farinae, while it was decreased in stimulated samples. The present results clearly indicated that stimulation by D. farinae increased mRNA expressions of Th2 cytokines but decreased that of Th1 cytokines in cultured PBMCs of high-IgE beagles.

Kinetics of phenotypic expression in whole bloods of high-IgE beagles during environmental allergen challenge

S. MAEDA*, H. TSUCHIDA*, E. CREARY† and R. MARSELLA†
*Department of Veterinary Internal Medicine, Gifu University, Gifu, Japan, and †Department of Small Animal Clinical Sciences, University of Florida, Gainesville, Florida, USA

The aim of this study was to evaluate kinetics of phenotypic expression in whole bloods from high-IgE beagles during environmental allergen (HDM, Greer Laboratories, Lenoir, NC, USA) challenge. The dogs were challenged 3 h day−1, 3 days in a row using a HDM solution. Clinical signs were evaluated before, during and after conclusion of challenge (days 0, 1, 2, 3, 4 and 17). Blood samples were obtained at each time point. Part of the blood samples were immediately placed in PAXgene tubes (PreAnalytiX, Feldbachstrasse, Switzerland) for expression analysis of cytokine mRNA (IL-4, IL-5, IL-10, IL-12, IL-13, IFN-gamma and TGF-beta) using a real-time polymerase chain reaction. The rest of the samples were used for a flow cytometric analysis to identify proportion of CD4 + positive for CCR4. Differences among days were analysed using two-way anova. If significant differences were found, Tukey–Kramer HSD test was used to detect significant differences. No significant mRNA expressions of IL-5, IL-12 and IFN-gamma were observed in any samples. Expressions of IL-4, IL-10, IL-13 and TGF-beta mRNA were detected in individual samples. There were no statistical differences on expression levels of IL-4 and IL-13 among different days. Expression of TGF-beta on day 4 was significantly lower than those on other days. It was also found that expression of IL-10 on days 4 and 17 was significantly lower than those on days 0 and 2. The highest CCR4/CD4 was observed on day 17. The present results indicated that environmental allergen challenge decreased expression of regulatory cytokines in whole bloods of high-IgE beagles.

Investigation on the clinical efficacy and tolerability of a 0.4% topical stannous fluoride preparation (MedEquine® gel) for the treatment of bacterial skin infections and pruritus in horses: a prospective, randomized, double-blinded, placebo-controlled clinical trial

R. MARSELLA, L. AKUCEWICH and J. LOPEZ
Blanche Saunders Dermatology Laboratory, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA

The purpose of this prospective, double-blinded, placebo-controlled clinical trial was to investigate the efficacy and tolerability of a gel containing 0.4% stannous fluoride (MedEquine®) gel for the treatment of cutaneous bacterial infections in horses. Twenty privately owned horses diagnosed with bacterial skin infections based on physical findings and cytology were enrolled and randomly assigned to either vehicle or active-ingredient treatment group. Product was applied on affected areas daily for 4 weeks. The quantity of gel applied was not standardized and owners were instructed to apply the product liberally to cover all affected areas. Cytology and clinical evaluations were done on days 0 and 28 by the investigator. Owners scored pruritus weekly. Both owners and investigators were blinded to the allocation to the groups. At the end of the study, stannous fluoride gel significantly decreased investigators’ clinical scores and owners’ pruritus scores. No changes were detected in the vehicle treatment group. At the end of the trial, none of the horses in the stannous fluoride group required additional therapy. Four of 10 horses in the vehicle group required systemic therapy to resolve the infection. No adverse effects were detected in any of the groups. It is concluded that stannous fluoride gel (MedEquine®) is an effective and safe therapy for the topical management of bacterial skin infections in horses.

This study was sponsored by Empire Pharmaceutical Inc.

Investigation on the effects of probiotics in Beagle puppies genetically predisposed to the development of atopic disease: a controlled, clinical and immunological study

R. MARSELLA and E. CREARY
Blanche Saunders Dermatology Laboratory, Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0126, USA

The purpose of this study was to evaluate the ability of probiotics to prevent or minimize atopic dermatitis (AD) in genetically predisposed dogs. For this purpose, high-IgE beagles suffering from severe AD when challenged with house dust mites (HDM) were bred. One female was bred twice, 1 year apart, to the same male. In the first pregnancy, probiotics were not administered while, in the second pregnancy, probiotics (Lactobacillus GG, Culturelle®) were started at week 3 of gestation (10 capsules/day) and continued throughout lactation. Both litters were weaned at 8 weeks. The second litter also received probiotics starting at 3 weeks of age (5 capules/day) and continued until 6 months old. Both litters were epicutaneously sensitized to HDM starting at 3 weeks until 6 months old. Blood samples were drawn monthly from 2 to 6 months of age and Dermatophagoides farinae-specific IgE were measured. At 6 months, both litters were skin tested and challenged with HDM. Clinical signs were scored. anovas were used to compare allergen-specific IgE, skin test results, and clinical scores. Seven puppies were born in the first litter and nine in the second. In the first litter, at 6 months of age, seven of seven puppies developed high D. farinae IgE, six of seven have positive skin test, and seven of seven developed severe clinical signs after challenge. In the second litter, seven of nine developed positive serology, three of nine have positive skin test, and six of nine developed dermatitis and pruritus after challenge. The second litter had significantly lower IgE titres, skin-test reactivity, while clinical scores, although lower, did not statistically differ.

This study was self-funded.

Environmental and oral challenge with storage mites in Dermatophagoides farinae sensitized high-IgE beagles

R. MARSELLA and E. CREARY
Blanche Saunders Dermatology Laboratory, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA

Thirteen high-IgE beagles sensitized to Dermatophagoides farinae developed high levels of IgE against storage mites. As these dogs are housed in an environment strictly controlled and storage mites could not be detected in either food or environment, this sensitization was interpreted as cross-reactivity with D. farinae. The purpose of this study was to determine whether this cross-sensitization is clinically relevant and whether lesions clinically compatible with atopic dermatitis (AD) could be elicited upon challenge with storage mites. High-IgE beagles were environmentally challenged with 50 mg of Tyrophagus putrescentiae (Greer, Lenoir, NC, USA), 3 days in a row. Dogs were evaluated before and 6 h after each challenge, and 24 h afterwards for a total of 5 days. A month later, dogs were orally challenged following the same protocol. CADESI was used to score clinical signs. Four healthy beagles, negative on serology and skin testing for both house dust and storage mites were used as controls. anovas were used to compare clinical scores between high-IgE beagles and controls and between types of challenges. Thirteen of 13 high-IgE dogs developed pruritic lesions of variable intensity, clinically compatible with AD, after both environmental and oral challenge. In both challenges, erythema developed on face, feet, pinnae and ventral abdomen. One to four controls developed mild pinnal erythema 6 h after challenge. anovas showed a significant effect of group and time and group–time interaction. High-IgE beagles had scores significantly higher than controls after challenge; scores increased overtime and were significantly higher after environmental challenge than after oral challenge.

A randomized, double-blind, placebo-controlled study to evaluate the use of a kiwiberry fruit extract (EFF1001) to decrease CADESI score and/or pruritus in dogs with atopic dermatitis

R. MARSELLA*, L. MESSINGER†, S. ZABEL‡, R. ROSYCHUK‡, C. GRIFFIN§, P. O. CRONIN¶, G. BELOFSKY¶, J. LINDEMANN¶ and D. STULL¶
*College of Veterinary Medicine, University of Florida, †Veterinary Referral Center of Colorado, Englewood, Colorado, ‡College of Veterinary Medicine, CSU, Fort Collins, Colorado, §Animal Dermatology Clinic, San Diego, CA, and ¶Efficas, Inc., Boulder, Colorado, USA

Kiwiberry fruit extracts are used in eastern medicine to treat inflammatory and allergic diseases. The purpose of the present double-blind, placebo-controlled study was to evaluate the efficacy of kiwiberry fruit extract (EFF1001) as adjunct therapy to prednisolone in dogs with mild to moderate atopic dermatitis (AD). Efficacy was measured using CADESI scores by clinicians and pruritus diaries provided weekly by owners over 4 weeks. Stage 1 of the study was a 2-week, prednisolone-only induction (days 1–3: 0.2 mg kg−1 b.i.d. PO; days 4–14: 0.2 mg kg−1 EOD PO) to stabilize the dog and ensure steroid response. Responsive dogs were then placed on 4 weeks of ‘adjunctive therapy’ with prednisolone (0.2 mg kg−1 EOD PO) and either placebo or EFF1001. Stage 2 was a 4-week, open-label ‘monotherapy’ for stage 1 responders to determine the efficacy of EFF1001 alone for continued management of AD. Seventy-seven dogs were enrolled at four sites between December 2005 and September 2006. Seventy-one per cent (55/77) of these dogs completed stage 1 and 64% (35/55) advanced to stage 2. Failure to complete in stage 1 was primarily due to secondary infections. Nineteen of the 35 dogs (54%) successfully completed stage 2. Seventy-nine per cent (15/19) of dogs completing stage 2 had received EFF1001 in stage 1 (P < 0.001) while 81% (13/16) of stage 2 failures had received placebo in stage 1. There were no significant differences in CADESI scores between treatment groups at the end of stage 1; however, pruritus was significantly reduced by EFF1001 when used adjunctively with low dose prednisolone (P = 0.03).

This study was supported by Efficas, Inc.

Clinical, histopathological and ultrastructural analysis of golden retriever ichthyosis

E. A. MAULDIN*, K. M. CREDILLE‡, R. W. DUNSTAN§ and M. L. CASAL†
Departments of Pathobiology* and Medical Genetics†, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA, USA, ‡Eli Lilly and Co., Indianapolis, IN, USA and §Pfizer Global Research and Development, Ann Arbor, MI, USA

A scaling disorder specific to golden retriever dogs has been well recognized by both dermatologists and pathologists, but to date, has been poorly characterized. At the University of Pennsylvania's Laboratory of Toxicology and Pathology, 45 cases of ichthyosis were diagnosed histologically in golden retriever dogs over a 23-month period (January 04–December 05). Twenty dogs had skin lesions documented at less than 1 year of age; three dogs between 1 and 2 years of age; 14 dogs developed lesions at greater than 2 years of age; the time of onset was unknown for eight dogs. Twenty-three dogs were female and 22 were male. All dogs had strikingly similar histopathological changes that consisted of moderate to severe laminar orthokeratotic hyperkeratosis with an absence of epidermal hyperplasia and dermal inflammation. Scattered keratinocytes with clear cytoplasmic vacuoles were located in the upper stratum spinosum/stratum granulosum. Ultrastructural analysis using ruthenium tetroxide fixation method was performed on punch biopsies of five dogs and compared with two control dogs (normal sibling of an affected dog, and a cairn terrier). The affected dogs had retained and convoluted membranes with crystalline structures in the stratum corneum. Scattered keratinocytes in the granular cell layer had large clear, membrane-bound, cytoplasmic vacuoles. Pedigree analysis of 14 dogs revealed a complex mode of inheritance. This unique hyperkeratotic/scaling disorder in golden retrievers has distinctive histological and ultrastructural features, which are most likely the result of a primary cornification defect.

This study was supported by a departmental research grant, University of Pennsylvania.

Study on efficacy and tolerance of detergents and solvents for cleaning heavily soiled hair coat and skin of dogs

U. K. MAYER*, J. G. THALHAMMER*, E. STAUDACHER† and M. SCHWANNINGER†
*I. Medizinischen Universitätsklinik für Einhufer und Kleintiere der Veterinärmedizinischen Universität Wien, Vienna, Austria, and †Institut für Chemie Universität für Bodenkultur, Vienna, Austria

Soiling of hair coats and skin with petroleum products is common in small animal practice (mean 2.4 cases/practice/year as per prestudy questionnaire mailed to Austrian veterinarians). Therefore, 18 detergents and 23 solvents and oils were tested for cleaning efficacy, first on glass and fabric, later on haired canine cadaver skin soiled with sump oil, heating oil or bitumen. Efficacy was evaluated colourimetrically from water samples taken from rinsing beakers. Samples were compared visually to 40 standard solutions of the petroleum product, the tested cleaning agent and tap water ranging in concentration from 0 to 0.1 volume percentage of the particular petroleum product. Sump oil and heating oil were most effectively removed by Dawn dishwashing soap® (Procter & Gamble, Vienna, Austria). To remove bitumen, pretreatment was needed, before cleaning with a detergent. Best results were achieved with Ökodiesel® (rapeseed oil methyl ester, Öhlmühle GmbH, Vienna, Austria) and Shell D70® (Shell GmbH, Vienna, Austria). However, butter and Penaten Baby oil® (Johnson & Johnson, Hallein, Austria) were also useful as pretreatment. A patch test on 10 laboratory beagle dogs was conducted to compare the effects of eight products on canine skin with two negative controls and a positive control (sodium lauryl sulphate). Both negative controls and PEG 400® (Propylenglycol) were well tolerated; only negligible irritation was seen for Dawn dishwashing soap® and Ökodiesel®; mild irritation for Radikalin (Hagleitner Betriebshygiene GmbH, Vienna, Austria), Pril Kraft Gel (Henkel, Vienna, Austria), Cupran (Stockhausen GmbH, Wolfurt, Austria), Shell T (Shell GmbH, Vienna, Austria) and Shell D70.

This study was self-funded.

Sugar inhibition of Malassezia pachydermatis to canine corneocytes

N. A. MCEWAN*, R. KELLY†, K. WOOLEY†, C. A. RÈME‡, H. GATTO‡ and T. J. NUTTALL*
*Department of Veterinary Clinical Science, University of Liverpool, Liverpool, UK, †Faculty of Veterinary Science, University of Liverpool, Liverpool, UK, and ‡Medical Department, Virbac SA, Carros, France

The authors, in previous studies, have shown that certain sugars inhibit the adherence of Pseudomonas aeruginosa and Staphylococcus intermedius to canine corneocytes. The aim of this study was to determine the anti-adhesive properties of a variety of sugar molecules including various monosaccharides, and alkylpolyglucoside (APG) against Malassezia pachydermatis. Three strains of M. pachydermatis obtained from the ear canals of dogs were used. Corneocytes were collected from the inner aspect of the pinna using an adhesive disc (D-Squame®). A 0.5-mL yeast suspension in phosphate-buffered saline (PBS), or sugar PBS solution, was placed over the corneocyte layer and incubated in a moist chamber. After 45 min incubation, the corneocytes were washed and stained. Adherent Malassezia were quantified using image analysis. The assay and counting methods were validated prior to sugar studies. Each of the three M. pachydermatis strains were used in each of six dogs and the anti-adhesive effect calculated as a percentage of the adherence without sugar. All monosaccharides studied failed to consistently reduce the adherence by M. pachydermatis. The alkylpolyglucoside did show anti-adhesive properties. Overall APG as a 0.5% solution was able to reduce adherence by M. pachydermatis to canine corneocytes by 41.9%. This study suggests that certain polysaccharides such as APG may have therapeutic potential in the treatment of Malassezia infections.

This study was supported by a research grant from Virbac SA.

Antimicrobial testing of canine otitis Pseudomonas aeruginosa isolates with marbofloxacin, enrofloxacin and orbifloxacin

L. W. MCKAY*, C. S. ROSE†, J. L. MATOUSEK*, L. S. SCHMEITZEL‡, N. M. GIBSON§ and J. M. GASKIN†
*VCA-Aurora Animal Hospital, Aurora, Illinois, USA, †Department of Infectious Disease and Pathology, University of Florida College of Veterinary Medicine, Gainesville, Florida, USA, ‡VCA-Berwyn Animal Hospital, Berwyn, Illinois, USA, and §Valdosta State University, Valdosta, Georgia, USA

Pseudomonas aeruginosa is commonly responsible for resistant bacterial canine otitis externa. Information regarding current susceptibility patterns of P. aeruginosa to individual fluoroquinolones is useful for selecting the most effective therapy. The purpose of this study was to compare the susceptibilities of P. aeruginosa to marbofloxacin, enrofloxacin and orbifloxacin using minimum inhibitory concentration testing (MICT). The present study also sought to assess agreement between MICT and disk diffusion susceptibility testing (DDT) to enrofloxacin and marbofloxacin for isolates of P. aeruginosa, as well as to determine whether DDT overestimates or underestimates the susceptibility of P. aeruginosa isolates compared to MICT. This study examined data from 100 canine otitis P. aeruginosa strains submitted to a university laboratory and those isolated by two private specialty practices. Paired samples Wilcoxon z-tests were computed on the data using spss, version 13. The P. aeruginosa isolates were significantly more sensitive to marbofloxacin than to enrofloxacin (z = −4.57, P < 0.05) or to orbifloxacin (z = −5.02, P < 0.05). The isolates were also significantly more susceptible to enrofloxacin than to orbifloxacin (z = −2.25, P < 0.05). An agreement of 87% was found when the susceptibilities to marbofloxacin obtained by MICT and DDT were evaluated. An approximately equal number of errors overestimated and underestimated the susceptibilities to marbofloxacin when MICT and DDT were compared. There was 74% agreement between MICT and DDT when the susceptibilities to enrofloxacin were compared. However, DDT tended to overestimate the number of enrofloxacin-susceptible strains when compared to MICT.

This study was supported by funding from VCA-Animal Hospitals.

A randomized, double-blinded placebo controlled cross-over study evaluating 0.03% tacrolimus ointment monotherapy in the treatment of discoid lupus erythematosus in dogs

L. MESSINGER*, T. STRAUSS*, L. JONAS† and V. FADOK‡
*Veterinary Skin and Allergy Specialists, Veterinary Referral Center of Colorado – Dermatology, Englewood, Colorado, USA, †Wheatridge Animal Hospital, Wheatridge, Colorado, USA, and ‡Gulf Coast Veterinary Specialists, Houston, Texas, USA

A randomized, double-blinded placebo-controlled cross-over study evaluated topical 0.03% tacrolimus ointment monotherapy applied twice daily for the treatment of canine discoid lupus erythematosus (DLE). Twenty-one dogs with histological confirmation of DLE were enrolled in the study. Dogs were allowed no other therapies typically used to treat DLE for 2 weeks prior to entering the study. Time spent outdoors was to remain the same throughout the study. During weeks 1–4 and 7–10, dogs were randomly assigned to receive tacrolimus or placebo; one treatment type per 4-week period. At weeks 5 and 6, dogs received no treatments. Dogs were evaluated by the investigators and owners on days 0, 28, 42 and 70 for depigmentation, cobblestone architecture, erythema, crusts, ulcers and overall disease severity. Complete blood counts and serum chemistries were also evaluated at each visit. Nineteen dogs completed the study; two dogs were lost to follow up, one after the first visit and one after day 42. The data were analysed via logistic regression (GLIMMIX procedure of sas) and via anova. No statistically significant changes were noted in any laboratory work parameters. Clinician assessment revealed statistically significant improvement in erythema (P = 0.04), crusts (P = 0.04), ulcers (P = 0.001) and overall disease severity (P = 0.003) when dogs received tacrolimus. Owner assessment revealed statistically significant improvement in cobblestone architecture (P = 0.04) when dogs received tacrolimus. A statistically significant change was noted in overall disease severity, where 13 of 18 (72%) dogs receiving tacrolimus improved, whereas only three of 19 (17%) improved on the placebo (P = 0008). Tacrolimus ointment can be beneficial in treating dogs with DLE.

This study was supported by a grant from the Morris Animal Foundation.

Dissemination of methicillin-resistant Staphylococcus intermedius in dogs: molecular evidence of clonal proliferation

D. O. MORRIS*, K. O'SHEA† and S. C. RANKIN†
*Department of Clinical Studies – Philadelphia, and †Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA

Staphylococcus intermedius continues to be the most commonly isolated pathogen from canine skin and soft tissue infections (SSTI). Although colonization and infection strains are usually the same within an individual, strains from different dogs are typically heterogeneous. Methicillin resistance (MR) in staphylococci has emerged as a major clinical and epidemiological concern in humans and animals. Human MR Staphylococcus aureus (MRSA) isolates have a clonal population structure, and global dissemination has occurred. We hypothesized that MR S. intermedius (MRSI) isolates from canine SSTI would also be highly clonal. Twenty-one unique MRSI isolates from 20 dogs were selected for inclusion in the study. All had an oxacillin minimal inhibitory concentration (MIC) of ≥ 1 µg mL−1, and were positive for penicillin-binding protein 2a. Pulsed field gel electrophoresis was performed and a dendrogram was prepared based on the Dice coefficient of similarity. Dogs were classified by zip code, referring veterinary practice, and admission date to our hospital. Seventeen unique pulsed-field profiles (PFP) profiles were observed and two clusters were identified. One large cluster, exhibiting > 80% similarity, contained the majority (15/21) of isolates. Nine dogs had been cultured on a first visit to our hospital, within 48 h of admission. Two dogs were referred by the same veterinary practice (5 months apart), while four dogs lived within two common zip code areas. However, each dog within a zip code pair had been referred by different practices, at least 14 months apart. These results suggest clonal proliferation of MRSI among the canine population in our region.

Clinical and histological evaluation of skin lesions in canine demodicosis

N. MURAYAMA, K. SHIBATA and M. NAGATA
Animal Dermatology Center, ASC Tokyo, Japan

Canine demodicosis has been described as an inflammatory skin disease associated with the overpopulation of demodectic mites, and considered to have various skin lesions. The purpose of this study was to identify the characteristics of skin lesions in this skin disorder. This study assembled 31 dogs with canine demodicosis, which were 11 localized and 20 generalized cases, and 21 juvenile-onset and 10 adult-onset cases. Diagnosis was based on (i) clinical findings; (ii) demonstration of demodectic mites in both skin scrapings, hair examination, and skin biopsy; (iii) ruling out differentials according to standard diagnostic procedures; and (iv) adequate improvement with avermectin treatment. Skin lesions observed in this study were classified into alopecia (29), erythema (19), hyperpigmentation (19), scales (14), papules (10), comedones (5), pustules (5), and crusts (2). Although those lesions are generally handled as nonspecific, close observation revealed several characteristic lesions: follicular papular erythema related to mural folliculitis and/or peri-follicular granuloma (6), follicular pigmented macules related to mural hyperpigmentation (6), diffuse psoriatic scales related to severe follicular hyperkeratosis (5), follicular erythematous dots related to peri-follicular vascular dilation (3), and patchy alopecia with comedones related to follicular hyperkeratosis (3). Those histological findings originated with hair follicles, and seem to reflect host reaction patterns against the mites. We conclude that canine demodicosis has both non-inflammatory and inflammatory skin lesions, and some lesions seemed valuable for the clinical and histological diagnosis. Further investigations are needed.

Cutaneous reactive histiocytosis in dogs: a retrospective evaluation of 32 cases

B. S. PALMEIRO*, D. O. MORRIS*, M. H. GOLDSCHMIDT† and E. A. MAULDIN*†
*Department of Clinical Studies – Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA, and †Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA

The University of Pennsylvania's Laboratory of Pathology and Toxicology database was searched for cases of canine cutaneous histiocytosis (CH) diagnosed between 1998 and 2006. Inclusion criteria consisted of: (i) histological and clinical findings consistent with CH, (ii) negative histochemical staining, and (iii) minimum follow up of 6 months. Thirty-two cases were retrospectively evaluated. Median age was 4 years. Breeds predisposed included Basset hounds, Border collies, collies, golden retrievers, and Shetland sheepdogs. Lesions included nodules/plaques affecting the head/face, trunk and limbs, and erythema/swelling/hypopigmentation of the nasal planum (NP)/nares. All dogs had complete resolution of dermatological lesions after initial treatment (median 45 days). Initial treatment included prednisone+/– antibiotics (12/32), prednisone and tetracycline/niacinamide (tc/niac) (7/32), prednisone and azathioprine (2/32), tc/niac +/– vitamin E/fatty acids (4/32), antibiotics +/– antihistamines (3/32), cyclosporine and ketoconazole (1/32), topical therapy (2/32), and no treatment (1/32). Seventeen dogs received maintenance therapy that consisted of tc/niac +/– vitamin E/fatty acids (12/17), cyclosporine/ketoconazole (2–3 times a week) (2/17), azathioprine daily (1/17), prednisone/azathioprine (two times a week) (1/17), and prednisone daily (1/17). Median follow up was 25 months. Nine dogs had a recurrence of CH (median days to recurrence 130 days), with seven of nine having > 1 recurrence. At study completion, six dogs were deceased (no lesions at the time of death) and 26 of 32 were alive with no lesions. Ten of 26 dogs were on maintenance treatment (8 tc/niac, 1 azathioprine, 1 vitamin E). Previous dermatological disease and season had no influence on recurrence. Recurrence was more likely in dogs with NP/nares lesions then dogs without (P = 0.03). Tc/niac is an effective treatment option for canine CH.

The quest for mites in horse barn dust samples

A. PETERSEN*, K. E. LOFT* and P. J. BOURDEAU†
*Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA, and †Unit Dermatology/Parasitology/Mycology – Department of Clinical Sciences, School of Veterinary Medicine, Nantes, France

Intradermal testing (IDT) in horses, with and without signs of allergic disease, frequently results in positive reactions to extracts of Dermatophagoides farinae (Df) and Dermatophagoides pteronyssinus (Dp). Cross- reactivity between house dust mite antigens (HDMA) and antigens of parasitic mites (Cheyletiella sp., Sarcoptes scabiei and Psoroptes ovis) is a common explanation for these reactions. However, because D. farinae and D. pteronyssinus can be found in outside environments such as nests of birds and other mammals, these reactions on IDT could support true hypersensitivity. The purpose of this pilot study was to examine dust samples from horse barns for the presence of house dust mites (HDM) and HDMA. Twenty-one dust samples were collected in October 2006 by vacuuming three locations each from seven barns. Samples were frozen (−20 °C) until analysed. Sucrose centrifugal flotation was performed for microscopic detection of mites and an ELISA was utilized to detect HDMA (Dp1, Df1 and group 2 allergens). Mites, morphologically similar to soil and storage mites, were seen in 10 of 21 samples but desiccation precluded definitive identification. Only two of 17 samples tested yielded ELISA results for Dp1 greater than 2 ng gram−1 of dust. In conclusion, mites and HDMA (Dp1) were detected in a limited number of horse barn dust samples. To further explore possible HDM hypersensitivity in horses, we suggest that future samples be collected in summer months (higher humidity) and examined fresh, rather than after a period of storage. In addition, dust/dander samples should be simultaneously collected from the hair coat of horses.

Correlation of nocturnal motion and observed pruritus in 15 dogs: a pilot study

J. D. PLANT
Department of Clinical Sciences, Oregon State University, Corvallis, Oregon, USA

An objective, valid and reliable method of measuring canine pruritus would be a valuable tool for researchers and clinicians in the field of veterinary dermatology. The objective of this study was to investigate the correlation of nocturnal motion measured with a piezoelectric accelerometer to observed nocturnal pruritus time (NPT) in 15 dogs. Animals included in the study were selected from the population of Heartland Humane Society based on temperament and severity of daytime pruritus. Each dog was housed in the same isolated run at the animal shelter for the evaluation period. Dogs were fitted with a collar-mounted accelerometer (ActiCal®; Mini Mitter, Bend, OR, USA), recording the duration and intensity of movement as activity counts (AC), derived from a proprietary algorithm. A video recording commenced when lights were turned out for the night (time 0), between 6:00 and 12:00 pm. Each video was analysed for the duration of pruritic behaviour for the period from 30 to 240 min. The observed NPT% was compared to the mean AC for the same period. Calculations were performed with statistical software (StatsDirect, StatsDirect Ltd, Cheshire, UK). The correlation coefficient (r) of the mean activity count and NPT% was 0.930 (95% CI 0.80–0.98). The relationship was described by the regression equation AC = 2.90 × (NPT%) + 1.73. The positive correlation observed provides additional evidence that piezoelectric accelerometers may serve as objective and valid measurement tools for nocturnal canine pruritus. Further studies are warranted to assess validity and reliability in clinical settings and in therapeutic trials.

The ActiCal device was funded by LeadDog, Inc., Talent, OR, USA, as part of a separate study.

Effect of an audience response system on student knowledge retention and satisfaction in didactic instruction of veterinary dermatology: a pilot study

J. D. PLANT
Department of Clinical Sciences, Oregon State University, Corvallis, Oregon, USA

Passive listening is associated with lower retention than active participation. The objective of this study was to determine if the use of an interactive audience response system (ARS) during veterinary dermatology lectures improved short- or long-term knowledge retention in third year veterinary medical students. A secondary objective was to obtain student opinions on the use of an ARS system during didactic lectures and ARS-directed case presentations. Twenty veterinary students were randomly divided into two groups. Both received one 40-min lecture per day for 5 days (period 1), each followed by 10-question, multiple-choice tests. Group A received presentations incorporating polling slides and an ARS (TurningPoint®), while group B received identical lectures without polling slides. Both groups participated in 4 h of ARS-directed case presentations. Fourteen students repeated the 50 test questions between days 33 and 49 (period 2). Students were surveyed regarding opinions on the use of the ARS. The mean test scores during period 1 for groups A and B were 80.3% and 77.6%, respectively. The mean test scores during period 2 for groups A and B were 51.6% and 57.0%, respectively. The differences between groups were not significant for either time period (P = 0.47 and 0.55). All students returning the survey (n = 12) rated the use of the ARS in the clinical veterinary curriculum favourably. Although short-term and long-term knowledge retention improvements were not detected in this pilot study, all students supported the use of audience response systems in veterinary education.

The audience response system was provided by Thomson Higher Education.

Repeatability and reproducibility of numerical rating scales and visual analogue scales for canine pruritus severity scoring

J. D. PLANT
Department of Clinical Sciences, Oregon State University, Corvallis, Oregon, USA

Numerical rating scales (NRS) and visual analogue scales (VAS) are commonly utilized to score the severity of canine pruritus in clinical trials. The objectives of this study were to determine the repeatability and reproducibility of NRS and VAS and to compare scales designed to score overall pruritus, intensity of pruritus, and duration of pruritus. Twenty-four veterinary students enrolled in the study. Sixteen randomly ordered 1- min video recordings of dogs displaying varying degrees of pruritus were viewed on three occasions: 0–25 min, 25–50 min, and 7 days. Observers scored each dog's pruritus with three NRS (0–5) and three VAS (0–100 mm). Short- and long-term intraobserver repeatability of the NRS and VAS were assessed with Cohen's weighted kappa (κw) and Kendall's rank correlation coefficient (τ), respectively. Interobserver reproducibility of the NRS and VAS was assessed with the Fleiss – Nee–Landis extension of Cohen's kappa (κ) and τ, respectively. The median κw of long-term repeatability for overall pruritus was 0.55 (range 0.30–0.83). The long-term repeatability of the three NRS was not significantly different. The median τ for long-term repeatability of the overall pruritus VAS was 0.72 (range 0.38–0.82). The overall pruritus NRS resulted in κ-values corresponding to ‘poor’ reproducibility for values of 2 and 3, ‘fair’ for 1, 4 and 5, and ‘moderate’ for 0. Under these experimental conditions the NRS displayed ‘fair’ overall reproducibility and ‘moderate’ long-term repeatability. Repeatability of pruritus NRS and VAS varied widely among observers.

This study was internally funded.

Prevalence of inappropriate presentation and analysis of ordered categorical data in the veterinary dermatology literature from January 2003 to June 2006

J. D. PLANT*, J. N. GIOVANINI† and A. VILLARROEL*
*Department of Clinical Sciences, Oregon State University, Corvallis, Oregon, USA, and †Department of Statistics, Oregon State University, Corvallis, Oregon, USA

Ordered categorical scales are commonly utilized in clinical trials to grade phenomena for which precise measurements on continuous or ratio scales are not available. Ordered categorical scales require statistical presentation and analysis methods consistent with the structure of the data. Inappropriate presentation and analysis of ordered categorical data is common in the human medical literature. The objective of this study was to determine the prevalence of inappropriate presentation and analysis of ordered categorical data in the veterinary dermatology literature. A PubMed search was performed with the following terms to select veterinary dermatology articles: (‘veterinary’[Subheading] OR ‘Veterinary Medicine’[MeSH] OR ‘Animals’[MeSH] NOT ‘Humans’[MeSH]) and (‘Dermatology’[MeSH Major Topic] OR ‘Skin Diseases’[MeSH Major Topic]). The search was limited to English language clinical and randomized controlled trials published from 1 January 2003 to 30 June 2006. Sixty-two of 74 articles identified met the inclusion criteria. The presentation and analysis of ordered categorical data were classified as appropriate or inappropriate. Forty articles (64.5%) from 16 journals utilized a median of four ordinal scales (range 1–13). Twenty-three of 40 articles (57.5%) contained inappropriate presentation of ordered categorical data. These included reporting inappropriate summary statistics (n = 17) and summation of ad hoc numerical rating scales (n = 15). Nine of 40 articles (22.5%) presented analysis of ordinal data utilizing inappropriate methods. These included inappropriate use of t-tests (n = 3) and analysis of variance (n = 6). The prevalence of inappropriate presentation and analysis of ordered categorical data in the veterinary dermatology literature are similar to that reported for several fields in the human medical literature.

This study was internally funded.

MIC range, MIC50 and MIC90 for nisin against Staphylococcus isolates from companion animals

S. C. RANKIN*, K. O'SHEA*, J. J. REJMAN†, J. H. CRABB† and D. O. MORRIS‡
*Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA, †ImmuCell Corporation, Portland, Maine, USA, and ‡Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA

Nisin is a polycyclic peptide antimicrobial produced by the fermentation of Lactococcus lactis. Nisin has been used as a food preservative for over 50 years. The aim of this study was to determine the minimal inhibitory concentration (MIC) range, MIC50, and MIC90 of nisin against methicillin-resistant (MR) strains of three significant Staphylococcus spp. isolated from companion animals. One hundred MR strains of Staphylococcus intermedius, Staphylococcus schleiferi, and Staphylococcus aureus from companion animals were screened for susceptibility to nisin using a broth microdilution technique as described by the Clinical Laboratory Standards Institute. Staphylococcus isolates were stored at −70 °C in Microbank tubes. The isolates were subcultured to blood agar plates and incubated at 37 °C overnight to ensure purity. Four or five well-isolated colonies were subcultured to 5 mL Mueller–Hinton broth and incubated at 37 °C until the turbidity matched that of a 0.5 McFarland standard. A 10 µL aliquot was used to inoculate broth microdilution plates that contained a range of nisin concentrations (3.125–3200 ng mL−1). Highly purified nisin was manufactured and supplied by ImmuCell Corporation. The MIC range was determined to be 3.125–3200 ng mL−1, the MIC50 was 800 ng mL−1 and the MIC90 was 3200 ng mL−1. Staphylococcus intermedius is the most prevalent staphylococcal species isolated from canine pyoderma. While all of the strains tested were highly susceptible to nisin, when the data were analysed independently by species, S. intermedius (N = 37) appeared to be the most susceptible with an MIC range of < 3.125–1600, an MIC50 of 200 ng mL−1 and an MIC90 of 800 ng mL−1.

A comparison of adrenocorticotropic hormone (ACTH) stimulation tests in normal dogs using a compounded ACTH gel vs. Cortrosyn™ (corticotrophin) – a pilot study

C. J. REEDER* and C. E. GRIFFIN†
*Animal Dermatology Clinic, Tustin, California, USA, and †Animal Dermatology Clinic, San Diego, California, USA

Adrenocorticotropic hormone stimulation testing (ACTH-ST) is a commonly performed test both for diagnosis and monitoring of dogs with hyperadrenocorticism (HAC). Two formulations of corticotrophin used in ACTH-ST in dogs are Cortrosyn™ (Amphastar Pharmaceuticals, Inc. Rancho Cucamonga, CA, USA) and ACTH gel made from compounding pharmacies. The previously available commercial ACTH gel is no longer produced and compounded product is frequently used. The purpose of this study was to compare the efficacy of a compounded ACTH gel to that of Cortrosyn™. Six normal dogs were included in the study. No topical, oral, or injectable glucocorticoids were given 2, 4, or 10 weeks, respectively, prior to inclusion. Three separate ACTH-ST were performed on each dog with a 5-day ‘washout’ period between each test. Cortrosyn™ and two separate lot numbers (A and B) of compounded ACTH gel were used. The ACTH gel was dosed at 2.2 IU kg−1 intramuscularly and the Cortrosyn™ was dosed at 5 µg kg−1 intravenously. The ACTH-ST protocol for the ACTH gel of both lots involved measuring blood cortisol level before injection (pre) as well as 1 and 2 h after (post) injections. When Cortrosyn™ was used, cortisol levels were measured pre-injection and 1 h post-injection. The results revealed that ACTH gel stimulated as good or higher than Cortrosyn™. This study confirms that this compounded ACTH gel and Cortrosyn™ may be used interchangeably for the diagnosis and monitoring of hyperadrenocorticism in dogs, and will be used in the next stage of my residency project.

This study was funded through the resident research fund of the Animal Dermatology Clinic.

Efficacy of topical 0.1% tacrolimus ointment in the treatment of canine familial dermatomyositis

C. A. REES
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Texas A & M University, College Station, TX, USA

Tacrolimus 0.1% ointment (Protopic: Astellas Pharma Manufacturing, Inc., Grand Island, NY, USA) is a macrolide produced by Streptomyces tsukubaensis medication indicated for the treatment of skin lesions associated with atopic dermatitis and peri-anal fistulas in dogs. The purpose of this study was to determine the efficacy of topical 0.1% tacrolimus in the treatment of canine familial dermatomyositis (DM). Inclusion criteria for dogs were: history and clinical lesions consistent with DM and evidence of DM on skin biopsies. Tacrolimus 0.1% ointment was applied to the skin of affected areas twice daily for 12 weeks. Dogs were evaluated on weeks 0, 4, 8 and 12. Physical examinations, measurements and descriptions of skin lesions and clinical photos were taken at each of these visits. The Student t-test (P = 0.05) was used to evaluate the pre- and post-treatment results. Complete blood counts, serum chemistries and urinalysis were collected during each of these visits. Eight dogs participated in the study. Three dogs (dogs 1, 5, 6) had complete resolution of the skin lesions on the legs. Three dogs (dogs 2, 6, 7) had complete resolution of the skin lesions on the tail tip. Significant improvement was seen in each of the dogs that participated in the study when comparing pre-drug vs. post-drug area values (P = 0.009). No adverse effects were noted when comparing pre- vs. post-drug blood work and urinalysis results. Topical application of 0.1% tacrolimus ointment is effective in the treatment of canine familial DM but response may be lesion location dependent.

This study was funded by the Canine Health Foundation.

Cyclosporine, ketoconazole and azathioprine combination therapy in three cases of refractory canine pemphigus foliaceus

W. S. ROSENKRANTZ*† and J. S. ANIYA†
*Animal Dermatology Clinic, Tustin, CA, and †Animal Dermatology Clinic, San Diego, CA, USA

Pemphigus foliaceus (PF) can be a difficult disease to control and often requires combination drug therapy. Three cases of well-documented canine PF had previously been treated with various therapies including glucocorticoids (GS), azathioprine (AZA) and antimicrobials. All failed to respond at moderate drug doses and developed secondary side-effects (hepatopathy 2/3 and bone marrow suppression 2/3). Combination AZA and cyclosporine (CsA) has been used in humans for renal transplantation, ulcerative colitis and other autoimmune diseases. Previous success utilizing CsA in canine PF has been anecdotal and often requires 10 mg kg−1 every 24 h or higher. The purpose of this report was to evaluate the response of combination AZA and CsA in three cases of refractory canine PF. Cyclosporine (Atopica®, Novartis Animal Health, Greensboro, NC) was added to a combined regimen of glucocorticoids, azathioprine and ketoconazole. Ketoconazole at 2.5–5 mg kg−1 every 24 h was utilized to increase serum levels of CsA. Induction dosages of CsA and AZA ranged from 7.5 to 8 mg kg−1 every 24 h and 1.5–2.5 kg−1 every 24 h, respectively. All drug dosages were tapered as clinical response was seen, with maintenance CsA ranging from 2.5 to 5 mg kg−1 every 48 h, AZA 1.5–2.5 mg kg−1 every 48 h and ketoconazole 2.5–5 mg kg−1 every 48 h. Glucocorticoids were completely stopped within 3–12 weeks after the addition of cyclosporine. All cases were in remission (10–18 month) with no clinicopathological abnormalities on the combined azathioprine, cyclosporine and ketoconazole protocol. This combined regimen should be considered as a therapeutic option for refractory cases of canine PF.

Assessment of cross-reactivity among five species of house dust and storage mites based on the results of intradermal testing and serology for allergen-specific IgE

M. N. SARIDOMICHELAKIS*, R. MARSELLA†, K. LEE‡, R. FARMAKI§ and A. F. KOUTINAS§
*Department of Clinical Studies, School of Veterinary Medicine, University of Thessaly, Karditsa, Greece, †Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA, ‡Greer Laboratories Inc., Lenoir, North Carolina, USA, and §Department of Clinical Studies, Faculty of Veterinary Medicine, Aristotles University of Thessaloniki, Thessaloniki, Greece

In vitro cross-reactivity among dust mite allergens has been suspected. This study was designed to evaluate cross-reactivity among Dermatophagoides farinae (DF), Dermatophagoides pteronyssinus (DP), Acarus siro (AS), Tyrophagus putrescentiae (TP), and Lepidoglyphus destructor (LD), using intradermal testing (IDT) and allergen-specific IgE serology (ASS) in 13 high-IgE responder beagles (group A) experimentally sensitized to DF without prior exposure to other mites, and 20 dogs with natural atopic dermatitis (group B). Five clinically healthy beagles were used as controls (group C). For IDT of groups A and C, three dilutions of each allergen were used, and reactions were evaluated subjectively and objectively. For group B dogs, IDT evaluation was objective and only one dilution of storage mite allergens was used. ASS was performed by two commercial laboratories. Of group A dogs, 38.5–100, 0–69.2, 30.8–76.9, and 7.7–61.5% reacted to DP, AS, TP and LD, respectively (IDT); the relevant figures for ASS were 76.9–100, 84.6, 76.9–84.6, and 46.2%. Among group B dogs, the covariations of sensitization between DF-DP, DF-AS, DF-TP, DF-LD, DP-AS, DP-TP, DP-LD, AS-TP, AS-LD, and TP-LD, were 0–50, 41.7–65, 38.5–70, 36.4–55, 0–64.3, 0–60, 0–61.5, 92.9, 84.6, and 78.6% (IDT), and 47.4–70, 95, 95–100, 52.6, 45, 45–70, 46.2, 100, 50, and 50% (ASS), respectively. Few positive IDT and ASS reactions were encountered in group C. The high covariation of sensitization (group B) raises suspicion for extensive cross-reactivity among dust mites, that was confirmed by the positive reactions of group A to dust mite species to which they had not been exposed.

This study was self-funded.

Effect of season on overnight dexamethasone suppression test results in aged horses without clinical signs of pituitary pars intermedia dysfunction

H. C. SCHOTT II*, S. W. EBERHART*, R. F. NACHREINER† and S. BEYERLEIN†
*Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA, and †Diagnostic Center for Population and Animal Health, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA

Pituitary pars intermedia dysfunction (PPID), more commonly known as equine Cushing's disease, is being increasingly recognized in aged horses. The diagnosis is established by recognition of clinical signs (hirsutism is nearly pathognomonic) and supportive endocrine test results. The latter include an elevated plasma adrenocorticotropin (ACTH) concentration and failure to suppress endogenous cortisol concentration in response to dexamethasone administration. Recently, endocrine test results in horses without clinical signs of PPID have been demonstrated to vary with season with false-positive test results reported in September. This finding has complicated diagnosis of PPID in horses. The purpose of this study was to further elucidate the effect of season on overnight dexamethasone suppression test (ODST) results by performing the test monthly for 1 year in groups of aged (> 18 years) Thoroughbred (TB, 2 geldings and 1 mare), Standardbred (STB, 3 mares and 2 stallions), Quarter horse (QH, 1 gelding and 1 mare), and Morgan (M, 3 mares and 5 geldings) horses without signs of PPID. All horses tested had normal ODST results in the months of November through April. However, abnormal ODST results (failure to suppress) were found in 13, 13, 47, 53, 40, and 40% of horses in May, June, July, August, September and October, respectively. There was no apparent breed or sex predilection for these abnormal test results. In conclusion, these results further confirm that endocrinological testing for PPID may be confounded during the summer and fall months. Thus, testing for PPID must be strategically timed to yield reliable results.

This study was supported by a grant from the Michigan Animal Health Foundation of the Michigan Veterinary Medical Association and additional funding provided by the Diagnostic Center for Population and Animal Health, Michigan State University.

Detection of Malassezia pachydermatis carriage by polymerase chain reaction in canine and human skin

J. A. SEO*, Y. I. KIM*, S. J. HWANG*, A. Y. JUNG*, Y. W. LEE†, S. J. YI* and T. H. OH*
*Department of Veterinary Internal Medicine, College of Veterinary Medicine, Kyungpook National University, Daegu, Republic of Korea, and †College of Veterinary Medicine, Chungnam National University, Dajeon, Republic of Korea

Malassezia pachydermatis serves as both commensal microorganisms and pathogen on the skin of dogs. It has been reported that human skin has no colonization by M. pachydermatis. Rarely, cases of life-threatening fungemia in people have been attributed to M. pachydermatis. This study was investigated the role of pet dogs as a risk factor for mechanical carriage of M. pachydermatis on human hands, as determined by microbiological culture and nested polymerase chain reaction (PCR) assay. Samples were collected using tape strip and swabbing method from the skin of dogs and palm of the human staff. DNA was extracted and amplified in a specific nested PCR. For statistical analysis, McNemar's test was used with statistical software (spss, version 12.0). One hundred dogs were divided into 40 healthy dogs and 60 dogs with M. pachydermatis overgrowth and their hospital staffs made up same groups. From the cytology-negative dog group, 25% of human samples were positive for M. pachydermatis growth on Sabouraud's dextrose agar and 62.5% of human samples were culture positive from the cytology-positive dog group. M pachydermatis-specific DNA was detected in 70% of human samples in the cytology-negative dog group and 82.5% of human samples from the cytology-positive dog group (P < 0.05). These results demonstrated that M. pachydermatis could be a risk factor for the mechanical carriage from dog to human, and the use of nested PCR is a sensitive and specific test for detection of cutaneous M. pachydermatis.

Expression analysis of TARC and TSLP in canine epidermal keratinocyte progenitors

S. SHIBATA*, S. MAEDA† and T. FUKATA*‡
*The United Graduated School of Veterinary Sciences, Gifu University, †Department of Veterinary Internal Medicine, Gifu University, and ‡Veterinary Teaching Hospital, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan

A CC chemokine, thymus and activation-regulated chemokine (TARC/CCL17), has been shown as a key molecule in immunopathogenesis of canine atopic dermatitis (AD). In recent studies, it has been indicated that a cytokine, thymic stromal lymphopoietin (TSLP) induces TARC production from murine dendritic cells. Thus, it is plausible that TSLP may also initiate TARC transcription in canine keratinocytes. The aim of the present study was to evaluate mRNA expressions of TARC and TSLP in canine epidermal keratinocyte progenitors (CPEK, CELLnTEC Advanced Cell Systems, Bern, Switzerland) and normal canine epidermal keratinocytes (NCEK) in order to elucidate mechanism of TARC production in vitro. Two different culture mediums, defined medium (defined keratinocyte-SFM, Invitrogen Corporation, Carlsbad, CA, USA) and undefined medium (CnT-09, CELLNTEC) were used for the cell culture. The cultured cells were harvested when the cells had reached approximately 80% confluency. Total RNA was isolated from the cultured cells and expressions of TARC and TSLP mRNA were examined by RT-PCR. In CPEK, TARC and TSLP mRNA were co-expressed in both culture conditions (defined and undefined). In contrast, NCEK did not express TARC and TSLP mRNA. These results indicate that expression of TARC by CPEK is a phenomenon specific to the cell line, and CPEK is useful to study mechanism of TARC production.

Transepidermal water loss correlates with skin barrier function in dogs

K. SHIMADA*, T. YOSHIHARA†, M. YAMAMOTO*, K. KONNO*, Y. MOMOI* and T. IWASAKI*
*Department of Veterinary Internal Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan, and †Kao Corporation, Tokyo, Japan

The skin barrier works to prevent water loss from skin and to defend the body from invasion by poisonous substances and microorganisms from the environment. Transepidermal water loss (TEWL) is thought to reflect the skin barrier function in humans. However, there are no known methods to evaluate quantitatively the skin barrier function in dogs. Using a newly developed device (CC-01), we evaluated if TEWL reflects the skin barrier function in dogs. Ten dogs with healthy skin were enrolled in the experiment. Skin barrier function was impaired by removing horny layers with 5, 10, 15, or 20 tape-stripping treatments. After each tape-stripping treatment, TEWL was measured with CC-01, and damage of skin surface was confirmed with a microscope camera and by histopathological examination. Actual change of skin permeability was evaluated by fluorescence application after tape stripping. TEWL was positively correlated with the frequency of tape stripping, increasing as the tape stripping frequency increased (P < 0.05, one-factor anova). Amount of fluorescence infiltrated into the skin increased subjectively after 10 tape-stripping treatments compared to after five tape-stripping treatments, and horny layers were confirmed to be completely removed. The microscope camera revealed dot-like erythema after 15 tape-stripping treatments. These results demonstrate that the horny layer seems to be involved in the skin barrier function in dogs as well as in humans. As TEWL values are closely correlated with the loss of horny layer, it is conceivable that TEWL reflects the skin barrier function in dogs.

The influence of polyunsaturated fatty acids on the T-cell response in dogs with atopic dermatitis

M. E. STEHLE*, T. GÖBEL†, M. HANCARUK† and R. S. MUELLER*
*Medizinische Kleintierklinik, Ludwig Maximilian Universität, Munich, Bavaria, Germany, and †Institute of Physiology, Ludwig Maximilian Universität, Munich, Bavaria, Germany

Eleven dogs with atopic dermatitis diagnosed based on Willemse's criteria and exclusion of differential diagnoses and 11 healthy control dogs were included in this study. Blood was obtained by venipuncture, and peripheral blood mononuclear cells were isolated. Cells were stimulated with concanavalin A and Dermatophagoides farinae extract in the presence of linoleic acid (LA), γ-linoleic acid (GLA), α-linoleic acid (ALA), eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) and GLA/EPA/DHA and proliferation indices determined. Proliferation indices were compared with a Friedman test and Dunn post-test and a P < 0.05 was considered significant. In presence of concanavalin A, healthy dogs showed a gradual reduction in the proliferation index from incubation without polyunsaturated fatty acids (PUFAs) to incubation with LA, GLA, ALA, EPA/DHA and GLA/EPA/DHA, respectively. This difference was statistically significant between control and ALA, EPA/DHA or GLA/EPA/DHA, respectively. A similar reduction was seen in the presence of allergen where all PUFAs but LA led to a significant reduction of proliferation. In contrast, the allergic patients showed a similar reduction only in the presence of allergen. This reduction was significant after incubation with ALA, EPA/DHA and GLA/EPA/DHA. These results indicate that PUFAs are able to influence proliferation of peripheral blood mononuclear cells in healthy and atopic dogs.

The authors are grateful to Ramona Schmitt und Birgit Viertlböck for her laboratory assistance, the staff of the veterinary teaching hospital in Munich for providing the healthy dogs and the dermatology service for providing the atopic patients and to Boehringer Ingelheim Danmark for financing the project.

Analysis of house dust mite (D. farinae) allergens in canine atopic dermatitis

T. TSUKUI*, M. SAKAGUCHI†, K. KURATA‡, S. MAEDA§, K. OHMORI¶, M. KOYANAGI*, K. MASUDA‡, K. OHNO¶, H. TSUJIMOTO¶ and S. IWABUCHI*
*Animal Life Science Laboratories, Nippon Zenyaku Kogyo Co., Ltd, Fukushima, Japan, †Department of Otorhinolaryngology, Chiba University, Chiba, Japan, ‡Research Center for Allergy and Immunology, RIKEN, Yokohama, Japan, §Department of Veterinary Internal Medicine, Gifu University, Gifu, Japan, and ¶Department of Veterinary Internal Medicine, The University of Tokyo, Tokyo, Japan

In the present study, we developed a new canine IgE detection system based on recombinant canine high affinity IgE receptor alpha chain (FcɛRIα) for analysis of major allergens in dogs with atopic dermatitis (AD). The canine FcɛRIα was expressed by an Escherichia coli expression system, whose IgE-binding activity on ELISA was verified with reduction by heat inactivation of mite-sensitized sera. Furthermore, the specificity of the IgE detection system was determined by inhibition assay with recombinant canine IgE. Using the assay system developed, we could detect house dust mite (Dermatophagoides farinae) allergen-specific IgE in dogs (N = 144) in which sensitization to D. farinae was also indicated by intradermal skin test. The present results showed that four major allergens (the molecular weight of 14 kDa, 85/78 kDa, 109/98 kDa and 188 kDa, respectively) were commonly reacted to canine IgE in 30–60% of the cases. The two of four allergens (14 kDa and 109/98 kDa) were found to be Der f 2 and Der f 15, respectively. Amino-terminal sequences of 188 kDa allergen did not show homology with those of major allergens that have been registered in NCBI Basic Local Alignment Search Tool Program, suggesting that these may be novel house dust mite allergens in canine AD.

Genetics and immunobiology of dermatomyositis in the Shetland sheepdog

J. M. WAHL*, L. A. CLARK*, O. SKALLI†, A. AMBRUS*, C. A. REES‡ and K. E. MURPHY**
*Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, TX 77843, USA, †Department of Cellular Biology and Anatomy, LSU Health Sciences Center, Shreveport, LA 71130, USA, and ‡Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, TX 77843, USA

Dermatomyositis (DM) is a canine and human inflammatory disease of skin and muscle that has been suggested to be autoimmune in nature. In the dog, DM occurs most often in the collie and Shetland sheepdog. Skin lesions are typically found on the face, ears, and distal extremities. Lesions vary in severity and are thought to be exacerbated by stressful stimuli. Studies suggest that DM is inherited in an autosomal dominant fashion with incomplete penetrance. Work presented here concerns the genetics and immunobiology of DM in the Shetland sheepdog. Gene expression profiles were generated for affected and normal skins using a canine-specific oligonucleotide array. Analyses revealed that 285 genes, many of which are involved in immune function, are differentially regulated in these tissues. Also reported are Western blot, immunohistochemistry, and immunofluorescence analyses that showed that staining patterns for normal and affected samples are quite similar. Our results suggest that canine DM is a disease that may be immune mediated but this does not likely include the production of disease-specific autoantibodies.

Idiopathic onychomadesis in Norwegian Gordon and English setter

M. L. ZIENER*, S. V. BETTENAY† and R. S. MUELLER‡
*Fredrikstad Animal Hospital, Fredrikstad, Norway, †Tierdermatologie Oberhaching, Oberhaching, Germany, and ‡Medizinische Kleintierklinik, Munich University, Munich, Germany

In Norwegian Gordon and English setters, a syndrome clinically resembling idiopathic onychomadesis or ‘lupoid onychodystrophy’ is reported. In this study medical records and claw biopsies of 18 Gordon and four English setters with idiopathic onychomadesis were obtained from July 2005 to September 2006. Only dogs with symmetrical onychomadesis and no other signs of concurrent disease were included in the study. Histopathological features varied between the dogs, but typically included features such as interface dermatitis with sub-epidermal cleft formation, pigment incontinence, basal cell vacuolization and necrosis, spongiosis and lymphocytic exocytosis, a lymphocytic, plasmacytic sub-epidermal inflammation and fibroplasia. In two dogs, histopathological signs of infection were present. A telephone interview was conducted with owners of affected dogs. There were 10 females and 12 males included in the study. Age of onset of disease varied between 2 and 7 years of age with a mean of 3.9 years. No correlation was found between vaccination time and onset of disease. The clinical work up varied between the dogs. Two of the affected dogs also have siblings with the disease. However, due to the close relationship of the affected dogs, pedigree map analysis was not possible. Two dogs were euthanized because of the disease, two had regrowth of normal claws (one was treated with polyunsaturated fatty acids, the other one additionally with prednisolone and niacinamide), but most dogs had persistent, although non-painful onychodystrophy on therapy, typically with polyunsaturated fatty acids.

This study was supported by the Norwegian Kennel Club and the Norwegian Gordon Setter Club.

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