NAVDF 2009 Abstracts


Staphylococcus schleiferi: biological characterization of an emerging canine pathogen

C. L. CAIN*, D. O. MORRIS* and S. C. RANKIN†
*Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
†Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA

Staphylococcus schleiferi is an emerging veterinary pathogen with two subspecies that have been characterized based on the production of coagulase; subsp. schleiferi (negative) and subsp. coagulans (positive). The aim of this study was to perform pulsed-field gel electrophoresis (PFGE) on 177 clinical S. schleiferi isolates from dogs to determine the degree of biological similarity of the two subspecies based on genotype. Isolates were identified by a commercial microbiology identification system as S. schleiferi and both slide and tube coagulase tests were performed. Antibiotic susceptibility data and biotype information were also recorded. mecA PCR and a PBP2a latex agglutination test were performed on all isolates. Clonal clusters were identified by PFGE with a similarity cut-off value of 80%. Of the 177 isolates, nine (5%) were determined to be another Staphylococcus species by PFGE. The majority of the remaining 168 isolates were obtained from skin (39%) or ears (49%); 68% were coagulase negative and 32% were coagulase positive. Sixty-eight per cent of coagulase-negative and 41% of coagulase-positive isolates, respectively, were oxacillin resistant. Fifty-five per cent of coagulase-negative and 33% of coagulase-positive isolates were positive by both mecA PCR and PBP2a latex agglutination. PFGE identified 11 major clusters; coagulase-positive and coagulase-negative subspecies clustered separately. Staphylococcus schleiferi subspecies are biologically distinct and both are pathogens of medical importance, although S. schleiferi subsp. schleiferi is more likely to be oxacillin resistant. Regardless of oxacillin susceptibility, trimethoprim-sulfamethoxazole was the most effective antibiotic tested.

This study was supported by a research grant from the American College of Veterinary Dermatology.

The use of ear wicks in canine otitis

L. N. GOTTHELF
Animal Hospital of Montgomery, Montgomery, Alabama, USA

Ear wicks have been used for many years in human otology and they are now gaining favour in veterinary otology. Ear wicks are porous polyvinyl alcohol sponges that expand and mould to the ear canal when moistened. Two case reports are presented and illustrated with video otoscopy showing the use of the ear wicks in infected and non-infected canine ears.

This study was self-funded.

Is cutaneous cytology useful in identifying Malassezia spp. in horse?

N. E. RADWANSKI*, R. CERUNDOLO* and S. C. RANKIN†
*Department of Clinical Studies , and †Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA

Previous studies in horses revealed that Malassezia organisms were easily visible via cytology; however, they often failed to grow on culture. The purpose of this study was to determine if cytology is an accurate tool to identify Malassezia yeasts and diagnose Malassezia dermatitis in equine patients. Four privately owned horses with normal skin were sampled. Samples were collected from the axilla, groin (preputial fossa or intermammary skin), tail base and perianal skin. Clear acetate tape was applied to each site, three times in succession, then stained with New Methylene Blue and applied to a glass microscope slide. Contact plates (3.5 × 1.0 cm) of Lemming's agar were then pressed against the skin at a site adjacent to that used for tape strip sampling. Plates were collected and incubated at 32 °C for up to 10 days. Colonies that grew on culture plates, with morphological and microscopic characteristics of budding yeast, were submitted for identification by DNA sequencing. The molecular identification of yeast cells was performed using the MicroSeq® D2 LSU rDNA Fungal Identification Kit (Applied Biosystems, Foster City, CA, USA). Yeast organisms with morphology consistent with Malassezia spp. were identified in all cytology samples. However, all cultured colonies were identified as various saprophytic yeasts including Candida, Myxozyma, Pichia, Dipodascopsis and Kluyveromyces spp. No Malassezia spp. yeasts were detected. This study confirms that cytology does not accurately distinguish saprophytic yeast from Malassezia spp. and that fungal culture with yeast speciation is a more accurate tool to identify yeasts residing on equine skin.

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

Investigation on the effects of ciclosporin (Atopica®) on intradermal test reactivity in atopic dogs

C. G. GOLDMAN*, E. J. ROSSER* and J. HAUPTMAN*
*Department of Small Animal Clinical Sciences, Michigan State University, College of Veterinary Medicine, East Lansing, Michigan, USA

The ability to use ciclosporin (Atopica: Novartis Animal Health, Greensboro, NC, USA) prior to intradermal testing (IDT) would help obviate exacerbation of clinical disease that can be associated with the required drug withdrawals. The purpose of this study was to evaluate the effects of 30 days of administration of ciclosporin at a dosage of 5 mg/kg every 24 h on IDT reactivity (immediate phase reactions) in a group of dogs with atopic dermatitis (AD) with initial positive IDT reactions. Sixteen dogs diagnosed with AD were included in the study. Eight dogs (group A) were treated with ciclosporin orally at 5 mg/kg once daily for 30 days, and eight dogs (group B) were treated with a placebo orally once daily for 30 days. IDT was performed at days 0 and 30 on all dogs enrolled using a standardized panel of 45 aqueous allergens (Greer Laboratories, Lenoir, NC, USA) appropriate to our geographical region. IDT reactivity was assessed by both subjective and objective methods at 15 min post-intradermal injection. The study was designed as a double-blinded, placebo-controlled study. Data were analysed by means of a split-plot analysis of variance with the grouping factor of treatment and the repeat factor of time (SAS System for Windows). At week 4, ciclosporin did not have an affect on IDT reactivity. In conclusion, ciclosporin has no effect on immediate phase reactions at 15 min post-intradermal injection. Therefore, no withdrawal is recommended to evaluate immediate phase reactions.

This study was supported by a grant from the American College of Veterinary Dermatology.

Resolution of clinical signs of canine glucagonoma-associated necrolytic migratory erythema with subcutaneous octreotide

U. OBERKIRCHNER*, K. LINDER†, L. ZADROZNY‡ and T. OLIVRY*
*Department of Clinical Science, North Carolina State University, Raleigh, North Carolina, USA
†Department of Population Health and Pathobiology, North Carolina State University, Raleigh, North Carolina, USA

Necrolytic migratory erythema (NME) is a syndrome most often associated with certain chronic liver diseases or pancreatic glucagonomas. In humans with glucaconoma-associated NME, skin lesions usually respond to octreotide, a somatostatin analogue that inhibits glucagon release. Our objectives are to report the remission of skin lesions of glucagonoma-associated NME in a dog treated with subcutaneous octreotide.

An 11-year-old golden retriever was diagnosed with pancreatic glucagonoma-associated NME metastatic to regional lymph nodes, spleen and liver. Because surgery was not an option, treatment was initiated with subcutaneous octreotide (2 mcg kg twice daily; APP Pharmaceuticals, Schaumburg, IL, USA). Skin lesions improved markedly within 5 days, as did systemic clinical signs. The dosage was increased to 3.2 mcg/kg twice daily and signs almost completely resolved within 10 days. Anorexia was the major adverse effect observed. During the following month, the dosage (1.2–3.2 mcg/kg) and frequency (two to four times daily) of octreotide injections were adjusted to permit control of clinical signs while maintaining appetite. Temporary cessation of octreotide administration resulted in the immediate recurrence of skin lesions. Resuming injections led to improvement of clinical signs within 48 h. The dog was later euthanized because of progressive metastatic disease. In conclusion, subcutaneous octreotide injections were beneficial in this dog with glucagonoma-associated NME. This inexpensive drug could be a valuable option to treat canine patients with non-resectable or relapsing pancreatic glucagonoma-associated NME.

This study was self-funded.

The novel high molecular weight Dermatophagoides farinae allergen Zen-1 is a major allergen in North American and European mite-allergic dogs with atopic dermatitis

T. OLIVRY*, S. M. DUNSTON*, C. FAVROT†, P. PRÉLAUD‡ and T. TSUKUI§
*Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
†Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
‡Clinique Vétérinaire Advetia, Paris, France
§Animal Life Science Laboratories, Nippon Zenyaku Kogyo Corporation, Koriyama-City, Fukushima, Japan

In Japan, Der f 2 and the novel 188 kDa allergen Zen-1 are major allergens in mite-allergic dogs with atopic dermatitis (AD). The objectives of this study were to determine whether these proteins were also major allergens in American and European mite-allergic dogs. Serum was obtained from 33 American (NC) and 29 European (Switzerland and France) dogs with intradermal and/or serological IgE reactivity to Dermatophagoides farinae (Df). Serum was collected also from 15 laboratory dogs epicutaneously sensitized to Df. An ELISA was performed using whole body Df, Zen-1, Der f 2 and Der f 1 and a monoclonal antibody specific for dog IgE. High levels of IgE against Zen-1, Der f 2 and Der f 1 were identified, respectively, in the serum of 88, 6 and 0% of Df-reactive American dogs; 90, 28 and 14% of Df-reactive European dogs; and 73, 33 and 60% of Df-sensitized laboratory dogs. Because of the high correlation between whole body Df and Zen-1-specific IgE serum levels, ELISA inhibition was done plating Df and incubating 11 American dog sera overnight with increasing amounts of Zen-1. At the plateau, Zen-1 inhibited a median of 60% (range: 28–84%) of Df reactivity. These results establish the novel high molecular weight protein Zen-1 as a major Df allergen in Df-reactive American and European dogs. The IgE reactivity to Zen-1 usually accounts for more than half of the total IgE reactivity to Df, making this allergen one of the most important Df allergen for dogs.

This study was funded by the Nippon Zenyaku Kogyo Corporation, Koriyama-City, Fukushima, Japan.

Allergen-specific IgE in atopic and healthy cats – comparison of rapid screening immunoassay and complete-panel analysis

A. DIESEL and D. J. DEBOER
Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, USA

Feline and canine atopic disease is thought to be immunopathogenically similar. As with dogs, detection of allergen-specific IgE in serum merely supports a diagnosis of feline atopy based on compatible history, clinical signs and elimination of other pruritic dermatoses. In this study, we compared the results of a rapid screening immunoassay (Allercept E-screen 2nd generation®, HESKA AG, Fribourg, Switzerland) and a complete-panel serum allergen-specific IgE assay (HESKA AG, Fribourg, Switzerland) in healthy cats with no history of dermatological disease (n = 18) and in atopic cats (n = 31). Atopic cats had no diagnosis of external parasitism, infection, food hypersensitivity, or other skin disease explaining their pruritus, and expressed cutaneous reaction patterns typically associated with feline allergic skin disease (head, neck, or pinnal pruritus; miliary dermatitis; self-induced alopecia; eosinophilic granuloma complex). Sera were assayed blindly. The complete-panel assay revealed no significant difference between detection of allergen-specific IgE in atopic version healthy cats (atopic cats: positive 20 of 31, healthy cats: positive 12 of 18; Fisher exact test –P = 0.242). There was, however, strong agreement between the results of the E-screen and complete-panel assay. Overall, the tests were in agreement for 43 of 49 (88%) serum samples (P < 0.001). There was also strong agreement when allergen groups were evaluated (agreement noted: indoor = 41 of 49, grasses/weeds = 37 of 49, trees = 41 of 49; all P < 0.001). These results indicate that although neither test is diagnostic for feline atopic dermatitis, the screening assay is beneficial for predicting the results of a complete-panel serum allergen-specific IgE assay in cats.

Sponsorship: Allercept E-screen 2nd generation® and full panel serum allergen-specific IgE assays were provided by HESKA AG, Fribourg, Switzerland.

A tyrosine kinase inhibitor targeting c-kit for chronic inflammatory diseases involving mast cells

O. HERMINE
AB Science USA, Short Hills, New Jersey, USA

Mast cell proliferation, differentiation and degranulation (the release of inflammatory cytokines and mediators that may have a physiological or pathological effect) is regulated by the growth factor receptor, c-Kit. Inhibitors of the c-Kit receptor may therefore have a beneficial effect in diseases conditions that involve mast cells. The objective of this work was to demonstrate the biological benefits of masitinib administration in three different in vivo rodent models of chronic inflammatory diseases.

In one model of allergic airway inflammation, Balbc mice sensitized to ovalbumin were given masitinib (25 or 100 mg/kg/day, p.o., after the sensitization process). Masitinib diminished significantly the airway hyper-responsiveness (30% reduction) during a methacholine challenge test (measured by the bronchconstrictive response) and significantly reduced the number of eosinophils in the bronchoalveolar lavage fluid (70% reduction) (n = 5, P < 0.05).

Similarly, in another model of dextran sodium sulphate-induced colitis in Balbc mice, masitinib dose dependently (25 mg/kg and 50 mg/kg) significantly reduced the symptoms (10% and 50% reduction of weight loss) and extent of macroscopic and histological lesions (25% and 50%) as well as colonic concentrations of myeloperoxidase (MPO) and inflammatory cytokines including tumour necrosis factor-alpha (n = 10; P < 0.05).

The results obtained from these in vivo studies in addition to our previous report regarding the beneficial symptomatic improvements noted in dogs with atopic dermatitis provide a rationale to perform studies with of c-kit inhibitors in other chronic inflammatory disorders involving mast cells in dogs including asthma and inflammatory bowel diseases.

Source of funding not declared.

The efficacy of imiquimod (Aldara®) in the treatment of equine aural plaque: an open-label pilot study

S. M. F. TORRES*, E. MALONE†, S. D. WHITE‡, S. A. N. KOCH* and J. L. WATSON‡
*Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, Minnesota, USA
†Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, Minnesota, USA
‡Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California, USA

Aural plaques affect at least 22% of horses and can be asymptomatic or cause ear sensitivity. Immunohistochemical and electron microscopy studies have shown strong association between aural plaques and papilloma virus. Reports of treatment options for aural plaques and their efficacy are few and all anecdotal. The purpose of this study was to investigate the efficacy of imiquimod, an immune response modifier with potent antiviral activity, in the treatment of equine aural plaques. Twenty-one horses were enrolled and 16 completed the study. Imiquimod was applied three times a week, every other week. When both ears were affected only the worst affected ear was treated. Side-effects in all horses included marked local inflammation, exudation and thick crust formation at the site of treatment and the adjacent skin. Removal of the crust before treatment was painful and required sedation in most horses. Complete resolution of lesions was noted in all horses. Duration of therapy ranged from 1.5 to 8 months (average: 3.3 months). Thirteen (81%) horses were followed-up between 12 to 22 months after treatment discontinuation and only one horse had recurrence of lesions. Clinical signs related to the aural plaques prior to treatment were reported in 10 of 16 (63%) horses and included resistance to touching the ears, clipping the ears and bridling. Complete resolution of these signs was reported by the owners in eight (80%) of the horses followed-up for at least 12 months. In conclusion, the topical application of imiquimod is successful in resolving aural plaques in horses.

This study was supported by the Minnesota Equine Research Center with funds provided by the Minnesota Racing Commission, the Agricultural Experimental Station and contributions by private donors. Imiquimod (Aldara®) was kindly provided by 3M.

Ultrasonographic study of the skin of shar pei dogs and correlation with hyaluronic acid plasma concentration

G. ZANNA, Y. ESPADA, M. J. DOCAMPO, D. FONDEVILA, A. BASSOLS and L. FERRER
Veterinary School, Universitat Autònoma de Barcelona, Barcelona, Spain

Shar pei dogs are affected by hereditary cutaneous mucinosis, an entity due to high dermal hylauronic acid (HA) synthesis and deposition that when severe, leads to pronounced skin folding and/or mucinous vesicles. To objectively evaluate the severity of mucinosis, skin thickness was measured by high-frequency ultrasonography and the results were correlated with the plasma hyaluronic acid levels. Ten healthy shar pei (six females and four males) affected by different degrees of mucinosis and 10 healthy beagles (seven females and three males) used as controls, were selected. Ultrasonographic examination of four cutaneous sites (frontal region, dorsal neck, sacral and left metatarsal regions) was conducted using a 13-MHz linear-array transducer. For each region, the mean value of three measurements was calculated. An ELISA was used to detect HA plasma concentration and data were compared with ultrasonographic measurements. In 10 shar pei the mean ± SD skin thickness was of 4.10 ± 0.56 mm when compared with control dogs (2.23 ± 0.41 mm). Skin thickness was greatest in the sacral region, followed by dorsal neck, frontal region and metatarsal region. A significant difference between the two groups (P < 0.05) was demonstrated in all the four sites examined. High levels of HA were detected in the plasma of shar pei dogs (4107.25 ng/mL) in comparison with the control group (823.41 ng/mL). Although a correlation could not be found between skin thickness and plasma HA, these results demonstrate that diagnostic ultrasonography may be a useful tool to assess the severity of cutaneous mucinosis in shar pei dogs.

Funded by Universitat Autònoma de Barcelona and Generalitat de Catalunya (SGR-2001-00208).

Safety and tolerability of 0.1% tacrolimus solution applied to the external ear canals of high-IgE beagle dogs without otitis

L. KELLEY*, A. FLYNN-LURIE*, R. HOUSE*, A. SIMPSON† and R. MARSELLA*
*Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
†College of Veterinary Medicine, University of Florida, Gainesville, FL, USA

Tacrolimus is a non-steroidal alternative to treat non-infectious otitis externa (OE) in people. This 21-day study investigated whether twice daily application (0.2 mL/dose) of sterile olive oil-based 0.1% tacrolimus solution in ears of atopic beagle dogs without OE was associated with adverse local reactions, development of OE, change in otic cytology, vestibular dysfunction or hearing loss detected by brainstem auditory evoked response (BAER). The study was randomized, double-blinded and placebo-controlled. Twenty-two dogs matched for age and sex were randomized to tacrolimus or vehicle control treatment groups. Two investigators independently evaluated dogs for signs of adverse effects including OE the first 4 days of treatment, then every 3 days. A logistic regression model was fit for each investigator's clinical scores (SAS, 9.2, 2008). Time (P = 0.0032) and group (P = 0.0167) were always significant for OE. Interobserver reliability of clinical scores was strong, measured using Kappa coefficients and proportion of agreement. All nine exclusions (7 of 11 control- and 2 of 11 tacrolimus-treated dogs) were excluded for yeast OE. Interobserver agreement to exclude was 100%. All dogs had normal BAER assessments before treatment, weekly during treatment, and after 21 days of treatment. None showed vestibular abnormalities at these times. Tacrolimus blood levels (Abbott IMx Tacrolimus II) were below detection limits (3 ng/mL) at baseline and after 21 days of treatment. Results suggest otic application of olive oil-based tacrolimus solution to canine ears with intact tympanic membranes is unlikely to result in hearing loss or vestibular dysfunction but yeast OE is a possible risk.

This study was supported by an educational grant from Merial Limited.

Detection of claudin-1 immunoreactivity in canine epidermal dendritic cells and canine cutaneous histiocytomas

K. E. LINDER*, P. BIZIKOVA†, K. BERMAN* and L. SHEWMON*
*Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
†Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA

Claudin-1 is a tight junction protein expressed in certain epithelial tissues and Langerhans cells in the skin of mice and people. Our objectives are to describe the pattern of claudin-1 immunoreactivity in canine epidermal dendritic cells (EDC) and cutaneous histiocytomas with initial comparison to two cutaneous epitheliotropic neoplasms in dogs – melanoma and epitheliotropic lymphoma. After retrospective review of paraffin-embedded surgical biopsies, processed at North Carolina State University, 24 cutaneous histiocytomas with confirmed positive immunoreactivity to CD18 and E-cadherin were selected along with six melanomas and six epitheliotropic lymphomas for immunohistochemical (IHC) analysis. OCT-embedded, fresh frozen, normal canine haired skin, lip and footpad were utilized for double-label IHC staining of EDC with CD1 and claudin-1. Twenty-four of 24 histiocytomas were positive for claudin-1, including the epitheliotropic cells. Under the staining conditions utilized, 0/6 lymphomas were positive and, in contrast to people, 0/6 melanomas were positive for claudin-1. Double-label IHC revealed dual positive membrane immunoreactivity of EDC for claudin-1 and CD1, but not for dermal dendritic cells. In all paraffin and frozen skin samples, canine epidermis and hair follicle epithelium exhibited positive immunoreactivity for claudin-1. Our results support expression of claudin-1 on canine EDC and the cutaneous histiocytomas that develop from these cells. Claudin-1 expression, at the level detected in this study, is not associated with cell migration in the epidermis in melanomas and epitheliotropic lymphomas. Claudin-1 may be a useful diagnostic marker for differentiating epitheliotropic round cell neoplasms in the dog.

This study was self-funded.

Evaluation of otoscope cone disinfection techniques and contamination level in small animal private practice

A. L. KIRBY*, W. S. ROSENKRANTZ†, R. M. GHUBASH*, B. NERADILEK‡ and N. L. POLISSAR‡
*Animal Dermatology Clinic, Marina Del Rey, California, USA
†Animal Dermatology Clinic, Tustin, California, USA
‡The Mountain-Whisper-Light Statistical Consulting, Seattle, Washington, USA

The objective of this study was to evaluate the level of contamination of otoscope cones in private practice, and to determine the most effective method of disinfection. Fifty-one small animal practices participated in the study, which included a detailed survey regarding otoscope cleaning, storage and usage. The hospitals were also informed that a quantitative culture of the cleaned stored otoscope cones would be performed. One hospital went out of business prior to culture; so only 50 hospitals completed the study. Using sterile technique, two cones from each of the 50 hospitals were swabbed and submitted for quantitative culture. 29% of the samples were contaminated and the organisms consisted of: Flavobacterium brevis (10%), Pseudomonas aeruginosa (6%), Pseudomonas alcaligenes (4%), Staphylococcus intermedius (4%), Corynebacterium spp. (2%), Bacillus spp. (1%), Enterococcus faecalis (1%) and Malassezia spp. (1%). There was no statistically significant difference between storage type (dry versus stored in solution) and for the instrumentation used to clean the cones (brush, cotton-tipped applicator, both versus none). There was a statistically significant difference between the different cleaning solutions (P < 0.001) and between the storage solutions (P = 0.003). A single most effective cleaning solution was unable to be determined due to the large number of solutions utilized. Cetylcide G® (Cetylite Industries, Inc., Pennsauken, NJ, USA) was the most effective of the three most commonly used storage solutions when used as directed (P < 0.001). The level of contamination had a positive association with the frequency of cone use and a negative association with the frequency of storage solution replacement.

This study was self-funded.

Comparison of the effect of tris EDTA (Tricide®)-ciprofloxacin-fluconazole-dexamethasone-ear drops with Baytril otic® in dogs with acute or chronic bacterial otitis externa

M. AUSTEL*, P. HENSEL*, R. E. WOOLEY† and B. W. RITCHIE*
*Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, USA
†Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, USA

The objective of this study was the comparison of the antimicrobial effect of tris EDTA/ciprofloxacin/fluconazole/dexamethasone (Tricide®, Molecular Therapeutics, Athens, USA) with enrofloxacin/silver sulfadiazine (Baytril otic®, Bayer AG, Leverkusen, Germany), both at a dose of 0.2 mL per 10 kg body weight every 12 h, in dogs with acute or chronic bacterial otitis externa. Twenty dogs diagnosed with chronic (26 ears) or acute (four ears) otitis externa were enrolled in this double-blinded, randomized study. Group A received Tricide®, group B, Baytril otic®. On day 0, otoscopic evaluation, cytological examination of ear smears, and bacterial culture and sensitivity testing with determination of minimum inhibitory concentrations and minimum bacterial concentrations for each aural bacterial isolate were performed. A total of 43 and 27 aural bacterial isolates were obtained from the dogs enrolled in treatment group A and B respectively; of these 17 and 11 respectively were resistant to enrofloxacin upon Kirby–Bauer disk diffusion testing. Cytology was repeated after 14 and 28 days. Administration of oral antibiotics or antifungals was not permitted. Nineteen dogs (29 ears) completed the study. There were no significant differences in change between baseline scores, from baseline values for total bacterial scores, bacterial rod scores, bacterial cocci scores, or fungal scores between the two treatment groups on days 14 or 28. The results indicate that both topical solutions are equally effective in the treatment of bacterial otitis externa although there is a 10-fold difference in antibiotic concentration per millilitre solution.

This study was supported by The University of Georgia Clinical Research Fund and the Georgia Research Alliance (GRA) Innovation Grants.

Disclosures: Dr. Ritchie is a co-owner of the company (Molecular Therapeutics, Athens, Georgia, USA) which manufactures Tricide®. None of the other authors have any financial benefit or affiliation with the company.

Nisin-impregnated wipes for the treatment of canine pyoderma and surface bacterial colonization

L. A. FRANK*, E. M. KIRZEDER*, J. A. DAVIS* and J. J. REJMAN†
*Department of Small Animal Clinical Sciences, University of Tennessee, College of Veterinary Medicine, Knoxville, Tennessee, USA
†ImmuCell Corporation, 56 Evergreen Drive, Portland, Maine, USA

Nisin is an antimicrobial peptide produced by Lactococcus lactis. Nisin is marketed in a wipe format to help prevent bovine mastitis. Recently meticillin-resistant Staphylococcus spp. isolated from companion animals were susceptible to nisin in vitro. The purpose of this research was to evaluate nisin wipes for treating surface infections and pyodermas in dogs. Study A enrolled 10 dogs with focal surface bacterial colonization. Cultures and cytology were obtained on day 0. Dogs were treated twice daily with nisin wipes and re-evaluated weekly. Study B enrolled 18 dogs with superficial pyoderma. Cultures and cytology were obtained on day 0. Two areas with similar lesions were selected and randomly assigned to receive either treatment or nothing. Nisin wipes were applied to the treatment areas twice daily. After 1 week dogs were started on clindamycin or another antibiotic based on culture and susceptibility and rechecked weekly. Visual assessment and cytology were performed at each recheck for both studies. In study A, Pseudomonas was cultured from five dogs and Staphylococcus intermedius from two dogs. The lesions of four dogs resolved with treatment while those with Pseudomonas and Malassezia did not. In study B, cultures from all but one dog yielded Staphylococcus intermedius susceptible to clindamycin. In 10 dogs treated areas showed improvement after 1 week and cleared more rapidly than the untreated areas. Mean time until cytological resolution was 1.4 versus 2.1 weeks. The mean time until clinical resolution was 2.5 versus 2.8 weeks. Nisin wipes demonstrated efficacy in treating some dogs with bacterial skin infection.

This study was funded by ImmuCell Corporation.

Evaluation of CLSI interpretive criteria for meticillin-resistant Staphylococcus pseudintermedius isolated from dogs

J. R. SCHISSLER*, A. HILLIER*, J. B. DANIELS*, L. K. COLE* and W. A. GEBREYES†
*Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA
†Department of Veterinary Preventive Medicine, The Ohio State University, Columbus, Ohio, USA.

The Clinical and Laboratory Standards Institute (CLSI) has recently revised the breakpoint guidelines for the minimum inhibitory concentration (MIC) of oxacillin used for the detection of meticillin resistance in coagulase-positive staphylococci (CPS) isolated from animals. The new guidelines state that ‘S. aureus interpretive criteria should be used for CPS such as S. intermedius’. We hypothesized that the new, increased oxacillin MIC breakpoint of > 4 µg/mL would under diagnose meticillin resistance in CPS isolated from dogs. Clinical isolates of meticillin-resistant S. pseudintermedius from dogs were continuously collected over a period of 20 months. Meticillin resistance was initially evaluated via oxacillin Kirby Bauer disk diffusion and oxacillin salt agar screening. The presence of the mecA gene was confirmed by polymerase chain reaction. The MIC for oxacillin was determined for each isolate by broth microdilution (Sensititre: Trek Diagnostic Systems, Cleveland, OH, USA). Thirty-four isolates of mecA-positive S. pseudintermedius were included. For 25 of 34 (73.5%) isolates the oxacillin MIC was ≥ 4 µg/mL. For eight of 34 (23.5%) isolates, the oxacillin MICs were 0.5–2 µg/mL and these isolates would have been incorrectly reported as meticillin susceptible according to the revised CLSI criteria. One (3%) of the isolates had oxacillin MIC ≤ 0.25 µg/mL, and would have been incorrectly reported as methicillin susceptible even with the previous CLSI interpretive criteria. The results of this study suggest that the application of the new CLSI criteria may significantly decrease the sensitivity of detecting meticillin resistance in mecA-positive CPS isolated from dogs.

This study was self-funded.

Investigation of the clinical efficacy of topical stannous fluoride for the treatment of canine superficial pyoderma

J. SELTZER*, A. FLYNN-LURIE*, R. MARSELLA* and M. BRENNAN†
*Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
†Department of Statistics, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, USA

Stannous fluoride (SF) is an antibacterial compound successfully used to treat gingivitis in humans and dogs and cutaneous bacterial infections in horses. The purpose of this prospective, double-blinded, placebo-controlled clinical trial was to investigate the efficacy of a 0.2% SF spray (Virapet®, Emerald3 Enterprises, Inc., Camdenton, MO, USA) for the treatment of canine superficial pyoderma. Twenty-six privately owned dogs diagnosed with bacterial skin infections based on dermatological examination, cytology and aerobic culture were enrolled. Dogs were then randomly assigned to the vehicle only or active ingredient treatment group. The product was applied topically to affected areas once daily for 28 days, with dogs being examined at days 0, 14, 28 and 42. Clinical and cytological evaluations were performed by the same investigators at each visit. Owners scored improvement of haircoat, odour and pruritus, and overall improvement at each recheck. Linear mixed models showed significant effect of group (P < 0.0001) and time (P = 0.0037) for investigator's scores and significant effect of time for owner's haircoat (P = 0.0077) and odour (P = 0.0170) improvement scores. Although dogs in both placebo and SF groups showed some improvement over time, investigator's scores on days 0 and 28 were not significantly different for both placebo and active ingredient group (P > 0.05) using t-tests. Spearman's rho correlation coefficients revealed significant negative correlation between investigator scores and all categories of owner assessment scores in dogs of both groups. Although some dogs improved on SF, this study does not support the use of 0.2% SF as sole therapy for canine superficial pyoderma.

This study was funded by Empire Pharmaceutical Inc.

Human and animal risk factor analysis for cross-transmission of methicillin-resistant staphylococci between veterinary dermatology practice staff and their respective pets

D. O. MORRIS*, R. C. BOSTON†, K. O'SHEA‡ and S. C. RANKIN‡
*Department of Clinical Studies – Philadelphia, †Department of Clinical Studies – New Bolton Center, ‡Department of Pathobiology, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, Pennsylvania, USA

It has been shown that veterinary professionals have a higher prevalence of subclinical nasal carriage of meticillin-resistant Staphylococcus aureus (MRSA) strains than the general human population residing in the USA, and that people living in close physical contact with each other may be colonized by identical strains of MRSA. The objective of this study was to test the hypothesis that domestic pets (dogs and cats) and people, when living in close contact, share colonizing strains of meticillin-resistant staphylococci. One hundred and seventy-one veterinary dermatology practice staff and their respective pets (258 dogs and 160 cats) were screened for MRSA, MR S. pseudintermedius (MRSP) and MR S. schleiferi (MRSS) by a swab technique, using selective media. Samples were shipped to the investigators’ laboratory by overnight carrier. Human subjects completed a 22-question survey of demographic and epidemiological data relevant to staphylococcal transmission. Human samples yielded six MRSA, nine MRSP and four MRSS isolates, while animal samples yielded eight MRSA, 21 MRSP and two MRSS isolates. Concordant strains (genetically identical by pulsed-field gel electrophoresis) were isolated from five persons and their respective pets: MRSA in two people/three pets and MRSP in three people/four pets. There were no demographic or epidemiological factors statistically associated with either human or animal carriage of MR staphylococci, or with concordant carriage by person–pet pairs. Lack of statistical associations may be due to an underpowered study. However, the MRSA isolation rate for people (3.5%) exceeded that documented for the general human population of the USA (0.84%) by a factor of 4×.

This study was supported by a research grant from the American College of Veterinary Dermatology.

Quantitative comparison of microorganisms obtained by repeated cytology of the ear canal of dogs with otitis externa

G. LEHNER*, C. SAUTER LOUIS† and R. S. MUELLER*
*Small Animal Medicine Clinic, and †Clinic for Ruminants, Veterinary Faculty, Ludwig Maximilian University, Munich, Germany

Eighty-three dogs with clinical signs of otitis externa and ear cytology revealing microbial organisms were included in the study. Specimens were collected from both ears of each dog by sequentially inserting two swabs into each ear canal, rotating them once by 360° and rolling them out in a line onto a glass slide. Four single parallel smears (SPS) were present (labelled) on one glass slide for each dog. Slides were subsequently stained with a modified Wright's stain. Six high power fields of every SPS were counted. Golden retrievers and West Highland White terriers were predisposed for otitis externa (Fisher exact test, P = 0.0006 and P = 0.0123 respectively). Otitis externa occurred significantly more frequently in dogs with pendulous pinnae than in dogs with erect ears (Fisher exact test, P = 0.0009). There was no significant difference in the number of microorganisms between the first and the second specimen (Wilcoxon's matched pairs tests, P > 0.1 for cocci and P > 0.5 for rods and yeast) and a substantial agreement between the results of the two subsequent swabs regarding the presence of cocci (Kappa = 0.765) and rods (Kappa = 0.705). Regarding yeast, the agreement was only moderate (kappa = 0.581). This study confirms the reproducibility of ear swab cytology used for the identification of microorganisms in otitis externa. However, the small number of divergent results emphasizes the importance of good monitoring and repeated otic cytology sampling of dogs with otitis externa, particularly with recurrent or non-responsive disease.

This study was self-funded.

Sporotrichosis: a retrospective evaluation of 23 cases seen in northern California (1987–2007)

S. L. CROTHERS*, S. D. WHITE*, P. J. IHRKE* and V. K. AFFOLTER†
*Veterinary Medical Teaching Hospital, Department of Medicine and Epidemiology, †Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA

Sporotrichosis is an uncommon to rare subcutaneous mycosis of animals and humans caused by the dimorphic fungus Sporothrix schenckii. Twenty-three mammalian cases of sporotrichosis examined between 1987 and 2007 at the University of California Davis – Veterinary Medical Teaching Hospital were retrospectively evaluated in regards to the historical, clinical, diagnostic and treatment findings. Cats were the most common species affected (n = 14). In addition, sporotrichosis was diagnosed in four dogs, four horses and a donkey. Six of 23 cases were diagnosed with the localized cutaneous form (three cats, one dog, one horse), 10 with the cutaneous-lymphatic form (four cats, two dogs, three horses, one donkey) and seven with the disseminated form (six cats, one dog). Two of 23 cases did not have skin lesions at the time of diagnosis. The most common mode of diagnosis was demonstration of S. schenckii on histopathological evaluation. In contrast with most previously described sporotrichosis infections in cats, few to no fungal organisms were seen in histopathological samples (haematoxylin and eosin and special stains) in five of the 14 cats. Treatments received included itraconazole (12 cats, one dog), ketoconazole (three dogs), fluconazole (one cat, one donkey), sodium iodide (four horses, one cat) and potassium iodide (one cat, one horse, one donkey). The prognosis for successful treatment was good in all species. Fluconazole was a successful treatment modality for disseminated sporotrichosis in one cat.

This study was self-funded.

Influence of a phytosphingosine-containing chlorhexidine shampoo on superficial bacterial counts and bacterial adherence to canine keratinocytes

A. STROH*, C. WERCKENTHIN†, C. SAUTER LOUIS‡ and R. S. MUELLER*
*Small Animal Medical Clinic, †Institute for Microbiology, ‡Clinic for Ruminants, Ludwig Maximilian University, Munich, Germany

Ten dogs (five healthy and five with atopic dermatitis) were bathed weekly four times with a shampoo containing phytosphingosine salicyloyl/chlorhexidine on one body side and shampoo vehicle on the other. Corneocytes were collected, before the first bath (day 1) and one (day 22) and five days (day 26) after the last treatment. Adhesive discs (four per site) were taken from both pinnae, left and right ventrolateral sides. Surface bacteria adhering were evaluated on the first disc. The corneocyte layers on three other discs were covered with a bacterial suspension, incubated at 37 °C for 45 min, washed, and stained with methylene blue. Organisms were counted in a blinded fashion.

Surface adherence counts of bacteria in the inguinal area were lower than on the pinnae in all dogs (P < 0.05). Counts after treatment were reduced at every site in every group, although the trend was for no significant differences between placebo and treatment sites on nearly all time points, groups and areas. However, counts were reduced statistically significant in atopic dogs on the sites treated with the chlorhexidine–phytosphingosine shampoo on day 22 and day 26. In healthy dogs, both shampoos decreased the surface bacterial count on the pinnae between day 0 and day 26 (P < 0.05). The count of adhered bacteria after incubation increased from day 0 to day 22 and day 26 respectively in almost all sites and groups (P < 0.001). Shampoo therapy was efficacious in reducing superficial bacteria on canine skin, but it did not reduce staphylococcal adherence to canine corneocytes.

The shampoo containing phytosphingosine salicyloyl/chlorhexidine was kindly provided by Sogeval, Laval, France.

Efficacy of topical management using 2% chlorhexidine acetate for canine superficial pyoderma

N. MURAYAMA*, M. NAGATA*, Y. TERADA*, S. SHIBATA† and T. FUKATA†
*Animal Dermatology Center, ASC, Tokyo, Japan
†Gifu University, Gifu, Japan

Canine pyoderma is becoming one of the intractable diseases with the emergence of the multidrug-resistant Staphylococcus intermedius group (SIG). Recently, the efficacy of 2% chlorhexidine was suggested in dogs with multidrug-resistant SIG-associated pyoderma. The aim of these studies was to evaluate the efficacy of 2% chlorhexidine acetate (Nolvasan Surgical Scrub: Fort Dodge Animal Health, Iowa, USA) (2CA) for canine pyoderma. Study 1 was a randomized, double-blind, controlled trial with 2CA and 10% ethyl lactate (Etiderm: Virvac JP., Osaka, Japan) (EL). Ten dogs with superficial pyoderma were allocated either 2CA or EL, 5 mL/150 cm2, at symmetrically different sites twice weekly. Pruritus, erythema, crusted papule and scale were scored in four grades. Seven dogs with 2CA were significantly improved compared to EL (P < 0.02). Study 2 using 2CA and 2% chlorhexidine gluconate (Malaseb: IVX Animal Health, Inc., FL, USA) (2CG), and study 3 using 2CA and 4% chlorhexidine gluconate (Skin Clinic Shampoo: CHD MEDICS, Goyang, South Korea) (4CG) were done in the same fashion. These two studies showed almost the same efficacy for 2CA, 2CG and 4CG. Study 4 was an open trial of 2CA monotherapy in eight dogs with cefalexin-resistant SIG-associated pyoderma, which was diagnosed based on susceptibility testing and clinical evaluation of oral cefalexin administration. 2CA was applied every other day for 2 weeks. Five dogs (62.5%) went into remission without antimicrobials, and one dog (12.5%) was better than before the trial. No adverse reactions were found in these studies. Topical management using 2CA proved effective in canine pyoderma.

This study was self-funded.

In vitro ceruminolytic activity of 24 ear cleaners against standardized synthetic canine cerumen

D. ROBSON*, D. MORTON†, G. BURTON* and R. BASSETT*
*Animal Skin Ear and Allergy Clinic, Melbourne Veterinary Specialist Centre, 70 Blackburn Rd, Glen Waverley, Victoria, Australia
†School of Pharmacy and Applied Science, PO Box 199, La Trobe University, Bendigo, Victoria, Australia

There is little objective information regarding the ceruminolytic activity of ear cleaners widely available in the USA or Australia. The aim of this study was to compare the ceruminolytic activity of ear cleaners primarily available in Australia and the USA using a previously described standardized in vitro testing procedure. Two millilitres of each test product was incubated in a shaking water bath for 20 min at 35 °C with approximately 500 mg of a synthetic standardized cerumen (SSC), followed by draining of product and dissolved or loose SSC. This procedure was repeated five consecutive times on each tube simulating repeated applications in the canine ear canal. Testing was duplicated for each product between two to eight times. Mean ceruminolytic activity (MCA) was assessed by quantifying the mean percentage of SSC removed by the test product over all duplicate tests. Results showed marked differences in MCA with 15 of 24 showing < 5% MCA, three of 24 showing 5–80% MCA and six of 24 (compounded alcoholic cleaner, Compoundia; Cerulytic, Virbac Animal Health; Leo Ear Cleaner, Boehringer Ingelheim; unnamed alcoholic cleaner, Ceva; Otoclean®, Laboratorios Dr Esteve SA; propylene glycol, Cattlekare) showing > 80% MCA. A low variability was seen between duplicate tests with the exception of one product. It is concluded that given the limitations of the experimental conditions used in this study, only six of 24 products had significant ceruminolytic activity.

This study was funded by a grant from the Animal Skin Ear and Allergy Clinic Research Fund. The Compoundia, Ceva and Vetxx products were supplied by the manufacturers.

Immunohistochemical detection of COX-2 in feline squamous cell carcinomas and feline and canine actinic keratoses

M. BARDAGÍ, D. FONDEVILA, G. ZANNA and L. FERRER
Animal Medicine and Surgery Department, Universitat Autònoma de Barcelona, Barcelona, Spain

Cyclooxygenase-2 (COX-2) has been shown to be overexpressed in some epithelial tumours and in human actinic keratosis (AK). COX-2 has been associated with tumour cell proliferation and angiogenesis. This relationship has provided a rationale for the use of anti-inflammatory drugs for the treatment of these disorders. The purpose of the present study was to detect COX-2 immunoreactivity in feline squamous cell carcinomas (SCC) and feline and canine AK. Forty-five samples (27 feline SCC, nine feline AK and nine canine AK) were investigated. Six canine SCC were used as positive controls. COX-2 immunoreactivity was detected in all feline and canine SCC. In all specimens basal and suprabasal positive neoplastic keratinocytes were associated with the presence of inflammatory cells. Only in four feline SCC, scattered positive basal cells were detected apparently not associated with inflammation. COX-2 immunoreactivity was detected in three of nine canine and four of nine feline AK, and in six of these cases, immunoreactivity was detected not associated with inflammation. These results were compared to 20 feline and canine inflammatory dermatoses in which positive keratinocytes were always associated with polymorphonuclear exocytosis. It can be concluded that COX-2 can be detected in feline SCC in contrast to previous reports. However, COX-2 immunoreactivity in canine and feline SCC appears to be associated to the inflammatory reaction rather than to the tumour itself. Contrarily, COX-2 expression in some AK may be related to AK pathogenesis. A further investigation of the correlation between the immunoreactivity and response to non-steroidal anti-inflammatory drugs could help to clarify this hypothesis.

This study was funded partially by the Universitat Autònoma de Barcelona and the Catalan Government.

Extraction of DNA from canine Demodex species, development of primers, and amplification of two Demodex canis DNA sequences

E. E. TOOPS*, S. C. LENAGHAN†, R. A. KENNIS*, J. M. MACDONALD*, B. L. BLAGBURN† and C. C. DYKSTRA†
*Department of Clinical Sciences, Auburn University College of Veterinary Medicine, Auburn, Alabama, USA
†Department of Pathobiology, Auburn University College of Veterinary Medicine, Auburn, Alabama, USA

Canine demodicosis occurs when large numbers of Demodex mites colonize hair follicles. Demodex mite characterization is based on morphological differences. Genetic analyses within Demodex species and between mite species would better characterize phylogenetic diversity and may assist in treatment strategies and understanding disease progression. Demodex canis mites were obtained during routine deep scrapings of three client-owned dogs and collected in Tris EDTA buffer (TE). Mites were separated from debris with a microhaematocrit suction apparatus. Outer chitin was ruptured using chitinase, glass beads and vortexing. Membranes and proteins were disrupted with sodium dodecyl sulfate (SDS) and proteinase K. Phenol/chloroform extraction, ethanol precipitation and resuspension in TE further purified the nucleic acids. After quantification in a Nanodrop™ spectrophotometer, 100 ng of mite DNA from one dog was amplified by a random amplified polymorphic DNA (RAPD) method as DNA yields were low. DNA was randomly cloned into plasmids and sequenced. The BLAST program in Macvector version 9.0™ was used to identify sequences that matched insect-type DNAs. Two oligonucleotide primer sets were designed to amplify mite DNA with polymerase chain reaction. One sequence was homologous to ubiquitin and the other matched bacteria commonly found as commensals in insects. The latter primer set amplified a similar sequence from flea and mosquito DNA. Neither amplified dog DNA. This method was successful in isolating DNA from Demodex canis mites. Oligonucleotide primers were developed that amplify Demodex sequences and will be useful in analysing phylogenetic relationships and may assist in understanding demodicosis progression.

This study was supported by Christine C. Dykstra gift accounts and by a departmental research grant, Auburn University College of Veterinary Medicine.

Response of feline eosinophilic cutaneous plaques and eosinophilic lip ulcers to amoxicillin–clavulanate therapy

B. E. WILDERMUTH*, C. E. GRIFFIN* and W. S. ROSENKRANTZ†
*Animal Dermatology Clinic, San Diego, California, USA
†Animal Dermatology Clinic, Tustin, California, USA

Randomized, double-blind, placebo-controlled study evaluating treatment of feline eosinophilic cutaneous plaques (ECP) and eosinophilic lip ulcers (ELU) with amoxicillin–clavulanate (Clavamox®: Pfizer Animal Health, NY, NY, USA). Response was assessed by measurement of lesion area (cm2) before and after treatment. Nineteen cats with clinical and cytological findings consistent with ECP and ELU were enrolled. On day 0, cats underwent flea combing, superficial skin scraping, dermatophyte culture, aerobic bacterial culture, skin biopsy, skin cytology and lesion photography. Cats were prescribed flavoured Clavamox® suspension 13.6 mg/kg average or flavoured placebo suspension orally twice daily for 21 days. On day 21, lesion cytology and photography were repeated. Lesions were measured using ImageJ software (NIH, USA) and analysed using a repeated measures model. Seventeen of 19 cats completed the study, one excluded due to positive dermatophyte culture and another whose biopsy indicated erythema multiforme. Nine cats with ECP (four in treatment, five in placebo) and eight cats with ELU (four in treatment, four in placebo group) were included in the analysis. The Clavamox®-treated ECP group had a significant decrease in plaque size (−7.60 cm2, P = 0.0018), while the placebo-treated ECP group did not (+0.07 cm2 P = 0.9597). The Clavamox® ECP group had a significantly greater decrease in plaque size compared to placebo (−7.67 cm2, P = 0.0078). The Clavamox®-treated ELU group had a decrease in plaque size (−0.27 cm2), and the placebo group an increase (+0.49 cm2); however, the changes were not statistically significant. The comparative change in plaque size between ELU groups was also not significant. Clavamox® is an effective treatment for eosinophilic cutaneous plaques.

Pfizer Animal Health and the Animal Dermatology Clinic funded this study.

Oral vitamin A in the treatment of canine sebaceous adenitis

A. T. H. LAM*, V. K. AFFOLTER†, B. GERICOTA† and S. D. WHITE‡
*Veterinary Medical Teaching Hospital, University of California – Davis, Davis, California, USA
†Department of Pathology, Microbiology and Immunology, University of California – Davis, Davis, California, USA
‡Department of Medicine and Epidemiology, University of California – Davis, Davis, California, USA

Medical records of dogs with sebaceous adenitis diagnosed via histopathology over a 17-year period were reviewed. Dogs with concurrent illnesses other than secondary skin infections were excluded from the study. Of 37 total cases fitting the inclusion criteria, 24 were treated with oral vitamin A. Patients ranged from 1 to 12 years of age at the time of diagnosis. Both purebred and mixed-breed dogs were affected. Akitas represented approximately one-third of the affected population. Sex predilections were not observed. Vitamin A was administered for a minimum of one month. Doses ranged from 380 IU/kg/day to 2667 IU/kg/day with a mean of 1034 IU/kg/day. Concurrent therapies included systemic antibiotics, antifungals, fatty acid supplementation and various topical treatments. Of the 24 dogs treated with vitamin A, four were lost to follow up. Ten owners were satisfied with the overall appearance of their dogs, reporting > 25% improvement in clinical signs, including level of pruritus, amount of scale, alopecia and overall coat quality as compared to pretreatment appearance. Two owners observed adequate initial improvement, with regression to pretreatment state within 6 months of starting therapy. Two owners reported 25–50% improvement in clinical signs while on oral vitamin A supplementation; however, attributed the changes to concurrent topical therapy. Six owners reported no improvement and discontinued vitamin A within 7 months. No correlations could be made between vitamin A dosage and response to treatment. Prognoses could not be made based on clinical and histopathological findings.

This study was self-funded.

Novel congenital acantholytic blistering dermatosis in Chesapeake Bay retrievers

K. E. LINDER*, T. OLIVRY†, J. A. BERNSTEIN‡ and P. BIZIKOVA†
*Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
†Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
‡Long Green Animal Dermatology Center, Baldwin, Maryland, USA

In humans, several hereditary dermatoses are due to acantholytic keratinocyte separation stemming from mutations of genes encoding either calcium pumps (Darier and Hailey–Hailey diseases) or desmosomal proteins (acantholytic epidermolysis bullosa). Our objectives are to report the clinical, histopathological and ultrastructural characteristics of a novel congenital acantholytic dermatosis in Chesapeake Bay retrievers (CBR). Nine puppies were affected out of 26 born in four litters in an inbred pedigree. The mode of transmission appears to be autosomal recessive. In all dogs, signs occurred immediately after birth with superficial epidermal layers sloughing off upon pressure. The three puppies kept alive for three months exhibited recurrent skin blistering with superficial sloughing and erosions at areas of friction and mucocutaneous junctions. In neonates that died within hours of birth, histopathology revealed a severe non-inflammatory disintegration of the epidermis with extensive acantholysis of suprabasal keratinocytes. As dogs aged, the epidermis became diffusely hyperplastic and hyperkeratotic, possibly as a compensatory change, while the severe acantholysis seen in neonates diminished in prominence. Electron microscopic examination of lesional epidermis of these older dogs revealed a reduced number or partially formed desmosomes with detached and aggregated keratin intermediate filaments. This novel dermatosis resembles both Hailey–Hailey and acantholytic epidermolysis bullosa of humans. The mode of transmission and perinatal onset of clinical signs in these CBR puppies is more suggestive of the latter. Future studies will look at the expression of calcium pumps and desmosomal proteins in affected skin in order to identify candidate mutated genes.

This study was self-funded.

Pilot study on the use of a product containing phytosterols, α- and γ-tocopherols and ω-3 and ω-6 fatty acids (Dermafit®, Supplexan, Germany) in dogs with atopic dermatitis

C. NOLI* and M. GALZERANO†
*Ospedale Veterinario Cuneese, Borgo San Dalmazzo, Cuneo, Italy
†Direzione Sanitaria AOU San Giovanni Battista, Torino, Italy

Phytosterols are natural vegetable preliminaries for hormones, enzymes and vitamins with anti-pruritic and anti-inflammatory effect. Natural α- and γ-tocopherols have a synergistic effect against free radicals, which are produced in inflammation. Omega-3 and omega-6 fatty acids support the endogenous regulation inflammation. Objective of this pilot study was to evaluate the efficacy of an oral supplementation containing these substances (Dermafit®, Supplexan, Germany) in decreasing signs of canine atopic dermatitis (CAD).

Ten dogs with CAD were treated for 4 weeks following the manufacturer's instructions. They had non-seasonal pruritus on extremities and ventral areas, no infections, no response to a hypoallergenic diet or parasiticidals, negative skin scrapings and fungal cultures, and positive skin tests for environmental allergens. Diet was not standardized but remained unchanged during the trial.

Pruritus, erythema and excoriations were evaluated before and after treatment on a scale from 0 (absent) to 3 (severe) in the areas of the head/neck, ventral trunk, dorsal trunk, anterior limbs and posterior limbs. A CADESI-01 was also performed.

Improvement was observed in nine of 10 animals. A mean decrease by 41% of pruritus, 50% of erythema, 78% of excoriations and 49% of the CADESI was observed. As variables distributions were normal with K-S test, a paired-samples Student's t-test was performed (P < 0.05). Mean differences were significant for pruritus (P = 0.006), erythema (P = 0.03) and CADESI (P = 0.01), but not for excoriations (P = 0.11).

These results are in line with other non-steroidal supplements used for CAD and are encouraging. A controlled study to confirm these results is anticipated.

This study was sponsored by Supplexan GmbH, Germany.

Demodex gatoi infestation in cats presenting with non-inflammatory alopecia

G. FERRER-CAÑALS, K. M. BEALE and V. FADOK
Gulf Coast Veterinary Dermatology and Allergy, Houston, Texas, USA

This retrospective study was designed to determine the incidence of Demodex gatoi in cats with excessive grooming and non-inflammatory alopecia (EGNA) in the Gulf Coast region of the USA. The records of 121 cats that presented with EGNA were evaluated. Based on skin scraping results and response to treatments, these cats were divided into four groups: group A: included 30 cats in which D. gatoi mites were found with skin scrapings; group B: 18 cats suspected of being infected with D. gatoi due to resolution of clinical signs with lime sulfur dips; group C: 53 cats that did not improve with lime sulfur dips; and group D: 20 cats for which treatment with lime sulfur dips was recommended, but were lost to follow up. Twenty five per cent of cats with excessive grooming and non-inflammatory alopecia were definitively infected with D. gatoi. Additionally, of the 71 cats that were not lost to follow up, with negative findings on skin scrapings, 25% had resolution of their skin condition with lime sulfur suggestive of D. gatoi infection. This demonstrates the importance of performing therapeutic trials with lime sulfur dips in cats with non-inflammatory alopecia regardless of findings on evaluation of skin scrapings. Distribution of lesions in cats of all groups was similar (commonly the lateral thorax, ventral and lateral abdomen, and medial aspect of all four limbs); and groups had similar age range (4 months to 16 years). Cats with D. gatoi seemed to have a poor response to systemic glucocorticoid therapy.

This study was supported by Gulf Coast Veterinary Dermatology and Allergy.

The prevalence of apoptotic epidermal keratinocytes in eosinophilic dermatoses of the cat: a retrospective light-microscopic study of 145 skin-biopsy specimens

J. S. GRIFFIN*, D. W. SCOTT* and H. N. ERB†
*Department of Clinical Sciences, Cornell University, Ithaca, New York, USA
†Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA

The purposes of this study were to determine (i) the prevalence of apoptotic epidermal keratinocytes (AKs) in eosinophilic dermatoses of the cat, (ii) the prevalence of eosinophils in close proximity to AKs, and (iii) if there was a difference in the prevalence of AKs and eosinophils in proximity to AKs based on histopathological reaction pattern. One hundred and forty-five specimens of feline eosinophilic dermatoses were reviewed by one author (JSG) who was blinded to the specific diagnoses. A 6-mm section on each slide (stained with haematoxylin and eosin) was examined for the number of AKs within the epidermis and the presence of eosinophils in proximity to the AKs. The cases were then separated into the following groups based on histological pattern: perivascular-to-interstitial, diffuse and nodular. Overall, 43% (62 of 145) of the specimens had AKs. Of the specimens with AKs, 18% had eosinophils within close proximity. No difference in the prevalence of AKs was found among the three histological groups (chi-square test, P = 0.42). Because the sample size containing eosinophils was too small to compare the three patterns, nodular and non-nodular patterns were compared, and no difference in the prevalence of eosinophils in close proximity to AKs was found (one-sided Fisher's exact test, P = 0.14). Wilcoxon rank sum test showed that more AKs were present if eosinophils were in close proximity to the AKs (one-sided, P = 0.03). This study indicates that AKs are commonly seen in feline eosinophilic dermatoses, and that eosinophils may be involved in triggering apoptosis in epidermal keratinocytes.

This study was self-funded.

Comparative IgE reactivity to house dust, storage and ear mites in serum of Channel Island foxes and dogs

T. W. VICKERS*, K. W. LEE†, R. E. ESCH†, W. BOYCE‡, L. MUNSON§, D. GARCELON* and D. L. CLIFFORD‡
*Institute for Wildlife Studies, Long Beach, California, USA
†Greer Laboratories Inc., Lenoir, North Carolina, USA
‡Wildlife Health Center, University of California, Davis, California, USA
§School of Veterinary Medicine, University of California, Davis, California, USA

Specific IgE reactivity to Dermatophagoides farinae (DF), Dermatophagoides pteronyssinus (DP), Tyrophagus putrescentiae (TP), Acarus siro (AS), Blomia tropicalis (BT), Lepidoglyphus destructor (LD) and the ear mite Otodectes cynotis (OC) was evaluated in 94 Channel Island fox (Urocyon littoralis) and 27 dog serum samples. Ear mites and sera were collected from foxes on San Clemente, Santa Catalina and San Nicholas islands; extracts of these mites remained island specific. Antigenic relatedness of fox and dog IgE was confirmed. Nearly two-thirds of all fox sera reacted to OC antigens; the concomitant response to the other mites were much less or nonexistent. The incidence of reactivity to DF, TP, AS and LD among fox samples was approximately 50%, and 15% to DP and BT. There was no apparent relationship between the magnitude of responses evident with the ear mite isolates and the magnitude of responses for the house dust and storage mites. The dog sample profiles of reactivity to the dust and storage mites varied and the individual responses ranged from negative to highly reactive. None of the dog sera that were highly reactive to any of the house dust or storage mites exhibited similar reactivity to any of the island ear mite isolates. Responses to ear mite allergens for dog sera were substantially less than the responses demonstrated for the fox serum samples and vice versa. Thus, it appears unlikely that there is a substantial shared antigen relationship between the fox ear mite isolates and the other mites evaluated.

This study was supported by Greer Laboratories, the Catalina Island Conservancy, and the Morris Animal Foundation.

Epidemiology of juvenile-onset, generalized demodicosis in dogs examined at a large, multi-location practice in 2006

J. D. PLANT*, E. M. LUND† and M. YANG†
*Banfield, The Pet Hospital, Portland, Oregon, USA
†DataSavant, Portland, Oregon, USA

Juvenile-onset, generalized demodicosis (JOGD) is considered a common skin disease of dogs. However, the basic epidemiology of the disease has not been well described. The reported prevalence rates and risk factors for the development of JOGD are often based on clinical impressions gathered from small or skewed populations. This study describes the epidemiology of JOGD from a large population of dogs seen in primary care practice throughout the USA. Electronic medical records for 1 189 906 dogs examined at 600 hospitals throughout the USA during 2006 were searched for a diagnosis of JOGD (onset < 18 months). A matched (by age and clinic) case-controlled logistic regression model was developed to assess risk factors for JOGD using statistical software (SAS version 9.2). There were 476 635 dogs under 18 months old; 3719 (0.78%) were diagnosed with JOGD. Mean age of cases was 0.5 years. Concurrent diagnoses (and odds ratios) associated with a diagnosis of JOGD were poor body condition (6.2), pyoderma (4.4), fleas (2.4), tapeworms (1.5) and roundworms (1.4). Diseases and conditions found not to be significantly associated with an increased risk of JOGD were: atopic dermatitis, coccidia, dermatophytosis, hookworms, kennel cough, otitis externa, pyotraumatic dermatitis, recent general anaesthesia and whipworms. The 10 breeds (and odds ratios) with the highest risk of developing JOGD were Chinese shar pei (21.7), American Staffordshire terrier (21.4), Pit bull (13.2), Boston terrier (12.1), English bulldog (10.6), boxer (8.7), American bulldog (8.5), miniature pinscher (8.2), great Dane (6.9) and pug (6.3).

This study was self-funded.

Characterization and quantification of ceramides in the non-lesional skin of canine patients with atopic dermatitis compared with controls

L. V. REITER*, S. M. F. TORRES† and P. W. WERTZ‡
*Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, Minnesota, USA
†Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, Minnesota, USA
‡Department of Oral Pathology, Radiology and Medicine. Dows Institute for Dental Research, University of Iowa, Iowa City, Iowa, USA

Similar to humans, there is mounting evidence in support of an abnormal skin barrier contributing to the pathogenesis of canine atopic dermatitis (AD). Studies in people with AD have associated an abnormal skin barrier with deficiencies in ceramides which represent important components of the stratum corneum (SC) intercellular lipid lamellae. Therefore, the goal of this study was to determine if the SC of dogs with AD is deficient in ceramides compared to normal dogs. Samples of SC were obtained from non-lesional skin of the caudal abdomen of 14 patients with AD and 14 age, breed and sex-matched healthy controls using a cyanoacrylate stripping procedure, and the sub-class and relative amount of ceramides were assessed blindly by thin layer chromatography. Paired t-tests using R statistical computer software revealed the percentage amounts of ceramides 1 and 9 were significantly lower in non-lesional skin of AD dogs compared to controls (P = 0.034 and P = 0.047, respectively), and the cholesterol percentage amount was significantly higher in AD dogs than in controls (P = 0.016). Furthermore, the cholesterol/ceramide ratio was significantly higher in the AD group with respect to controls (P = 0.014). These findings suggest that decreased amounts of ceramides in the skin of dogs with AD may be involved in the impaired barrier function of their skin.

This study was funded by the Novartis American College of Veterinary Dermatology Resident Research Award and the University of Minnesota College of Veterinary Medicine Small Companion Animal grant.

The influence of Mometamax® (mometasone furoate) on intradermal test immediate reactions in atopic dogs

K. M. MURPHY* and T. OLIVRY*
*Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA

The objective of this study was to determine what if any influence percutaneous absorption of the corticosteroid contained in Mometamax®, mometasone, has on intradermal allergy test reactions. Twenty atopic dogs, all candidates for immunotherapy, were entered into the study. Selection criteria included the presence of active otitis externa, seasonal allergic disease, withdrawal of topical and oral corticosteroids for 4 weeks; injectable corticosteroids for 8 weeks, and antihistamines for 14 days. On day 0 of the study, 0.2 mL of two positive controls (histamine and anti-canine IgE) and one negative control (saline) was injected intradermally. Twenty minutes later measurements were taken, and the global wheal score (GWS) was determined for each control. The Mometamax® was dispensed and the owner instilled a specific amount into each affected ear every 24 h for 14 days. On day 14, the procedures were repeated and if the GWS was determined to be within 25% of the value on day 0, the study was completed. If the GWS had decreased by 25% or more of the value on day 0, the Mometamax® was withdrawn in increments of 7 days, with determination of the GWS every 7 days until the value was within 25% of the original GWS. Three of 20 dogs completed the study on day 14, while 17 of 20 dogs completed the study on day 21. These results show that a withdrawal period of 7 days or less is possible in dogs with active otitis externa treated with Mometamax® prior to allergy skin testing.

This study was funded by Schering-Plough Animal Health.

The effects of lyophilized grapefruit juice and metoclopramide on the pharmacokinetics of ciclosporin in dogs

N. E. RADWANSKI*, R. CERUNDOLO*, F. S. SHOFER* and M. H. COURT†
*The University of Pennsylvania, School of Veterinary Medicine, Department of Clinical Studies, Philadelphia, PA, USA
†Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, Boston, MA, USA

Ciclosporin, a calcineurin immunosuppressive agent, has been used in veterinary medicine for various dermatoses. Drug combinations which inhibit ciclosporin metabolism such as grapefruit juice and metoclopramide, although well studied in humans, have not been extensively studied in the dog. The objective of this study was to characterize the absorption and pharmacokinetics of ciclosporin (Atopica: Novartis Animal Health, Greensboro, NC, USA) in eight healthy mixed breed dogs after oral administration of either (i) ciclosporin (5 mg/kg) alone, (ii) in association with a single oral dose of metoclopramide (0.3–0.5 mg/kg), (iii) when combined with lyophilized grapefruit juice (L-GFJ; 4 × 500 mg capsules) or (iv) when combined with both metoclopramide and L-GFJ. The dogs were randomly assigned into a latin square design of four treatment groups to eliminate order effects. Each dog received all four treatments with a 14-day washout period between treatments. Blood samples were collected over a 24-h period, and whole blood concentrations of ciclosporin were analysed by high-performance liquid chromatography. Analysis was accomplished with pairwise comparisons to ciclosporin alone by ANOVA with post-hoc Dunnett's test. There were no significant changes in ciclosporin area-under-the-curve, clearance, time to maximum concentration or maximum observed concentration in any of the treatment groups compared with ciclosporin alone. The results indicate that ciclosporin metabolism is not inhibited in the dog by metoclopramide or L-GFJ at the doses used in this study. Further studies are needed to evaluate effects of higher doses of L-GFJ on ciclosporin in the dog.

This study was funded by the Novartis resident research grant from the American College of Veterinary Dermatology.

Efficacy of metaflumizone plus amitraz for treatment of juvenile and adult onset generalized demodicosis in dogs: pilot study of 24 dogs

W. S. ROSENKRANTZ
Animal Dermatology Clinic, Tustin, CA, USA

A spot-on formulation containing metaflumizone plus amitraz (ProMeris®/ProMeris Duo® for dogs, Fort Dodge Animal Health, Overland Park, KS, USA) was evaluated in 24 dogs with juvenile (n = 13) or adult onset (n = 11) generalized demodicosis. Case selection included option for initial therapy by owner preference (3 of 24), undesirable side-effects of previous treatment (6 of 24) or lack of efficacy of previous treatments (15 of 24). All were treated with a minimum dose rate (20 mg/kg of metaflumizone and amitraz, 0.133 mL/kg) at a 14-day interval until two consecutive negative skin scrapings were obtained. Cases were evaluated every 30 days. The treatment times ranged from 90–180 days. The results were based on reduction of mite numbers. A grading score was assigned as excellent if no mites were identified for 60 days (two negative scrapings), good if 75% reduction, fair if 50% reduction and poor if no change in mites numbers within 90 days. Other antimicrobial therapies were allowed throughout the study. Cases were monitored for side-effects and complications. Of the 13 juvenile onset cases, 12 of 13 (92.3%) had excellent results and one of 13 (7.7%) had poor results. In the 11 adult onset cases, five of 11 (45.4%) had excellent results, three of 11 (27.3%) had good results and three of 11 (27.3%) had poor results. Side-effects included a pemphigus foliaceus-like pustular eruption (1), vomiting (1), diarrhoea (2), transient lethargy (2) and product odour (7). Efficacy was comparable to other products, and metaflumizone plus amitraz is an approved alternative to other treatment options. Longer term remission and cure rates still need to be evaluated.

The spot-on formulation metaflumizone plus amitraz (ProMeris®/ProMeris Duo® was supplied by Fort Dodge Animal Health, Overland Park, KS, USA.

Determination of irritant threshold concentrations of six mites through serial dilutions in intradermal testing on healthy clinically non-allergic dogs

C. L. BAUER*, P. HENSEL*, M. AUSTEL* and D. KEYS†
*Department of Small Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
†Statistical Consultant, Athens, Georgia, USA

Intradermal allergy testing concentrations for dust and storage mites commonly induce positive skin test reactions. One explanation for this could be the use of testing concentrations which exceed an irritant threshold concentration inducing false positive reactions. The purpose of this study was to determine the irritant threshold concentration (ITC) of six mites for intradermal testing (IDT) in 37 healthy, clinically non-allergic dogs. Six allergens, two dust mites and four storage mites, were tested at five variable concentrations ranging from 10–250 PNU/mL. ITCs were determined by evaluating the lowest concentration to which no dogs (0% cut-off) and to which at least 10% of dogs (≥ 10% cut-off) reacted. ITCs at the 0% cut-off were: 10 PNU/mL for Dermatophagoides farinae and Tyrophagus putrescentiae, 25 PNU/mL for Acarus siro and Lepidoglyphus destructor and 75 PNU/mL for Dermatophagoides pteronyssinus. For Blomia tropicalis the 0% cut-off was < 10 PNU/mL and could not be determined. ITCs at the ≥ 10% cut-off were: 50 PNU/mL for B. tropicalis, 75 PNU/mL for A. siro, D. farinae, and L. destructor, 100 PNU/mL for T. putrescentiae and 200 PNU/mL for D. pteronyssinus. Based on these results it is suggested that ITCs for the mites tested may vary and that testing at concentrations greater than 200 PNU/mL may induce clinically non-relevant positive reactions. Further studies are needed to evaluate the benefit of lower IDT concentrations for house dust and storage mites in atopic dogs.

This study was funded by the American Academy of Veterinary Dermatology Research Grant. Material support was provided in part by Greer Laboratories Inc., Lenoir, NC, USA.

Multiple digital Histoplasmosis in a cat. As initial clinical presentation

A. BERROCAL*, A. GONZÁLEZ† and J. PRENDAS‡
*Private Service, A.P.-904, Heredia 3000, Costa Rica
†Private Service, El Coyol, Alajuela, Costa Rica
‡Laboratorio de Micología, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica

Histoplasma capsulatum is a saprophytic dimorphic fungus of tropical and subtropical regions. It is reported mainly in young cats where it can produce systemic infections, likely acquired via aerosol with respiratory signs. Rarely, this can lead to disseminated dermal presentation. Alternatively, solitary skin lesions may be produced by direct wound inoculation.

A 7-year-old shorthaired spayed female cat was presented for evaluation of three nodules (< 0.4 cm) in the claw bed of both front limbs. Cytological examination (Giemsa stain) showed predominantly macrophages, which contained numerous small round bodies (2 to 4 µm in diameter), with an evident halo and yeast-like structures. Histopathological analysis (haematoxylin and eosin, PAS and GMS stain) showed lymphocytes, plasma cells and fibroblasts. Additionally, many macrophages had structures consistent with H. capsulatum. It was isolated in Sabouraud media plates and identified based on colony morphology.

The patient was treated with fluconazole for 6 weeks with complete clinical recovery. A year later, the cat began to lose weight significantly and show mydriasis. Additionally, small nodules (< 0.3 cm) were present in both upper eyelids and oral cavity. Histology and cytology revealed similar organisms as the previous year, and clinical relapse was suspected. Euthanasia was elected due to lack of response to treatment and progressive deterioration. In the literature, the dermal form of histoplasmosis has been considered infrequent. To the authors’ knowledge this clinical presentation has not been reported yet. Especially in adult cats, this is an important differential of cutaneous nodules.

This study was self-funded.

Reliability of intradermal allergy tests in dogs with atopic dermatitis

G. FERRER-CAÑALS*, J. D. PLANT†, K. M. BEALE* and V. A. FADOK*
*Gulf Coast Veterinary Dermatology and Allergy, Houston, Texas, USA
†Banfield, The Pet Hospital, Portland, Oregon, USA

Intradermal testing (IDT) is considered the most reliable tool (the ‘gold standard’) by which to identify allergens for immunotherapy. Although IDT has been used in atopic dogs for decades, its reliability has never been reported. The purpose of this study was to evaluate the reliability of IDT by assessing repeatability (agreement of replicates) and reproducibility (agreement among multiple observers).

IDT was performed using allergenic extracts (Greer Laboratories, Lenoir, NC, USA) in 12 client-owned atopic dogs. Responses were graded using a semiquantitative scale from 0 to 4, where 0 represented responses equivalent to those induced by saline and four represented responses induced by histamine. For each test, 15 allergens were injected in duplicate, with the replicate being blinded. Repeatability was determined for each investigator by comparing the two scores for each of the replicated allergens. Reproducibility was determined by comparing the scores between pairs of investigators and then among all three for the 15 allergens that were blinded. Repeatability and reproducibility were assessed using Cohen's weighted kappa (Kw). The Fleiss-Nee-Landis extension of kappa for multiple raters evaluated the combined reproducibility of the three investigators.

The repeatability of IDT scoring was found to be ‘fair’ to ‘moderate’ with Kw values ranging from 0.34 to 0.56. Overall reproducibility was considered fair (0.27). The reproducibility for low scores (1, 2) was fair, but scores of ‘4’ showed very good reproducibility among the three investigators. We conclude that IDT appears less reliable than one would expect for a technique considered ‘Gold Standard’.

This study was funded by Gulf Coast Veterinary Dermatology and Allergy.

Intense facial pruritus associated with Demodex injai infestation: a report of 10 cases

Peter J FORSYTHE, Silvia T AUXILIA and Hilary A JACKSON
Dermatology Referrals, Glasgow, Scotland

Nine shih tzu dogs and one Scottish terrier presented with intense facial pruritus. Demodex injai was identified. No gender predilection was noted. The age of onset was 6 months to 6 years of age (median 2 years). Additional problems included a history of recurrent otitis (six of 10), pododermatitis (five of 10) and conjunctivitis (three of 10). Previous treatments included antimicrobials, antihistamines, glucocorticoids and topical moxidectin and imidacloprid (Advocate®). Two dogs were febrile and inappetant. Clinical signs included intense facial pruritus (10 of 10), erythema (10 of 10), alopecia (six of 10), scaling (four of 10) crusting (one of 10), papules (two of 10), seborrhoea oleosa (two of 10), swelling (one of 10), tear staining (one of 10), hyperpigmentation (two of 10) and hypopigmentation (one of 10). The lesions affected the periocular skin (seven of 10), chin (three of 10), muzzle (four of 10), ears (three of 10), lips (three of 10) and bridge of the nose (one of 10). Mites were identified on deep skin scraping under sedation and also on trichography in two cases. Mite numbers were typically scarce. Concurrent Malassezia and bacterial infections were common. In one case clinical signs and histological lesions consistent with pemphigus foliaceus were present. The dogs were treated with ivermectin (eight of 10) at a maximum dose of 0.6 mg/kg per day per os or milbemycin oxime (two of 10) at a dose of 1.57–2.2 mg/kg for periods of between 3 and 9 months. The median treatment duration to resolution of facial pruritus was 2 months and to parasitological cure 4 months. In six dogs treatment was withdrawn after clinical and parasitological cure. Two of the six dogs relapsed within 4 months. Demodex injai infestation should be considered a differential diagnosis for facial pruritus.

This study was self-funded.

Serological and intradermal test reactivity patterns among six species of house dust and storage mites

P. HENSEL*, C. L. BAUER*, M. AUSTEL* and D. KEYS†
*Department of Small Animal Medicine, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA
†Statistical Consultant, Athens, Georgia, USA

Although the significance of dust mites as an important source for atopic dermatitis has been recognized, the validation of positive results has not been elucidated in depth. Serology and intradermal testing (IDT) were performed in 32 clinical healthy non-allergic dogs for two house dust mites: Dermatophagoides farinae (DF), D. pteronyssinus (DP), and four storage mites: Blomia tropicalis (BT), Tyrophagus putrescentiae (TP), Acarus siro (AS) and Lepidoglyphus destructor (LD). All dogs reacted to at least one allergen in the serology test, whereas 23 of 32 of dogs had a positive IDT reaction to at least one allergen. Most common reactions (serology versus IDT) were observed for the following mites: DF (96.875% vs. 62.5%), AS (87.5% vs. 59.375%), TP (87.5% vs. 43.375%) and BT (65.625% vs. 53.125%). Less common reactions were observed for DP (43.75% vs. 15.6%) and LD (6.25% vs. 34.375%). Concurrent positive reactions among different mites were significant for most mites in IDT (except between DF and DP). Serology revealed strong co-reactivity between DF and TP, TP and AS, as well as DP and BT. Skin test-positive dogs had significantly higher mean serology values for DP, DF, AS and BT than dogs with a negative skin test. In conclusion, positive reactions to dust mites in serology and IDT are very common in clinically healthy, non-allergic dogs, making a correct interpretation difficult. Also, the dogs reacted in general to more than one mite, indicating cross-reactivity or concurrent exposure to different mites.

This study was self-funded.

Efficacy of oral blackcurrant seed oil supplementation for the prevention of signs of seasonal canine atopic dermatitis – a placebo-controlled study

C. NOLI* and M. GALZERANO†
*Ospedale Veterinario Cuneese, Borgo San Dalmazzo, Cuneo, Italy
†Direzione Sanitaria AOU San Giovanni Battista, Torino, Italy

The aim of this work was to evaluate the efficacy of the oral supplementation with blackcurrant seed oil (BSO) in the prevention of seasonal exacerbations of canine atopic dermatitis. Fourteen dogs with seasonal atopic dermatitis, with pruritus and skin lesions occurring for at least two consecutive years, without flea allergy and under flea control were included. BSO (100 mg/kg/day – seven dogs) or a placebo (seven dogs) was started 2 months before the expected period of development of signs. Pruritus (visual analogue scale) and lesions (CADESI) were evaluated the previous summer, on inclusion day and after 2, 3 and 4 months, and results were compared. In 43% of the treated animals pruritus did not appear at all or was very mild, in 43% it was decreased and only in 14% it did not change. In the control group pruritus did not appear in 28% of the cases, was decreased in 14% and unchanged in 58% of dogs. In the treated animals CADESI were decreased in all treated dogs, and were < 50% in 71% of dogs. In the control group lesions were decreased only in 42% of dogs. Development of pruritus and CADESI scores were significantly decreased in the treated group if compared to the placebo or to the previous summer (P < 0.05). The oral supplementation with BSO at the dosage of 100 mg/kg/day can represent a valid help in decreasing or inhibiting the development of clinical signs and pruritus in seasonal canine atopic dermatitis, if started at least 2 months before the critical period.

This study was funded by NBF Lanes, Milan, Italy.

Multiple (disseminated) follicular cysts in a dog – a case report

D. SANTORO*, C. A. LICHTENSTEIGER† and K. L. CAMPBELL*
*Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
†Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA

Single follicular cysts are common in dogs, cats, horse and humans. Their aetiology is unknown. This report describes an unusual manifestation of multiple, widely disseminated follicular cysts in a dog. A 5-year-old female spayed mixed breed dog presented with a 2-year history of recurrent subcutaneous nodules widely distributed over the body. The dog had more than 40 lesions predominantly involving the dorsum, legs and the head. The nodules varied in size from ∼0.5 to 3 cm in diameter. The skin overlying some nodules was alopecic with white adherent scales. Differential diagnoses included follicular cysts, nodular sterile panniculitis, dermatofibromas, mast cell tumours, histiocytosis, deep fungal infection and mycobacteriosis. Cytology revealed a few macrophages, neutrophils, cocci and numerous keratinocytes embedded in amorphous sebaceous debris. Multiple excisional skin biopsies were taken for histopathology as well as fungal, aerobic bacterial and mycobacterial cultures. Cultures were negative except for rare colonies of Staphylococcus intermedius. Histopathologically, the nodules were dermal cysts extending into the panniculus. The cysts were lined by keratinizing stratified squamous epithelium with a granular layer. They were filled with laminated concentric keratin, and supported by a band of fibrous tissue. The fibrous tissue had a moderate accumulation of macrophages, including a few multinucleated giant cells, lymphocytes, plasma cells and occasionally some neutrophils. The findings are typical of infundibular follicular cysts. Although widely disseminated infundibular cysts are rare in dogs, they should be included as a differential for multiple subcutaneous nodules or masses in dogs.

This study was self-funded.

Topical supersaturated oxygen therapy in canine and equine dermatoses

L. B. STOKKING* and R. M. ROSE†
*Veterinary Specialty Hospital, San Diego, California, USA
†PetMedicus Laboratories, Inc., Sioux Falls, South Dakota, USA

We report the results of an open-label prospective study investigating potential applications of a supersaturated oxygen emulsion in treatment of chronic skin conditions in dogs and horses. In addition to responding to increased metabolic demand in tissue repair, oxygen plays several roles; it is required for phagocytosis, neovascularization oxygen-dependent microbial killing and serves as a growth factor. Previously reported experimental studies of a topical supersaturated oxygen emulsion showed a dose-dependent increase in fibroblast proliferation and an increased rate of epithelialization of experimentally induced partial-thickness wounds and second-degree burns in pigs. Thus, topical oxygen therapy is expected to accelerate resolution of infection, enhance epidermal repair and hasten wound healing. The agent used in the study is a patented perfluorocarbon-based emulsion of supersaturated oxygen that delivers dissolved oxygen at high partial pressures to the skin surface (ZoonOx: PetMedicus Laboratories, Inc., Sioux Falls, SD, USA). Our study population consisted of five horses with pastern dermatitis, pyotraumatic dermatitis, and/or decubital ulcers; nine dogs with pododermatitis, skin fold dermatitis, and/or pyotraumatic dermatitis; and one Chinese crested dog with comedone-associated folliculitis and furunculosis. Twice-daily application of test material induced no pain, erythema or irritation. Decrease in lesion severity score was observed by day seven in all dogs with skin-fold dermatitis, pyotraumatic dermatitis and pododermatitis and in all horses with pastern dermatitis. Decubital ulcers in horses decreased in size, but did not resolve completely. This study shows that topical supersaturated oxygen is an appropriate and well-tolerated adjunctive or single-agent therapy in veterinary dermatology patients.

This study was supported by PetMedicus, Inc.

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