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During the second year of her residency in dermatology, my resident (M. D. Clark, personal communication, 2012) asked me to look at a 5-week-old healthy male pitbull dog. Whitish, mildly adherent scale was present on the skin and in the hair coat over the rump and dorsal trunk. The skin and hair coat were otherwise normal, and one of the puppy's seven littermates – also a male – was likewise affected. No diagnostic investigations or treatments were performed, and the condition spontaneously resolved over the course of 3 months in both puppies.

Flashback! During the first year of my residency in medicine, my mentor (R. W. Kirk, personal communication, 1972) introduced me to my first puppy with what he called ‘cradle cap’. The puppy was a healthy 6-week-old, male basenji whose five littermates were unaffected. White, mildly adherent scale was present on the skin and in the hair coat over the rump (Figure 1). Areas of the hair coat – with scale attached to the base of the hairs – were clumped together and lifting off, revealing normal skin and regrowing hair coat underneath. Skin scrapings, acetate tape preparations and fungal culture were all negative. The puppy received no treatment, and the condition spontaneously resolved over the course of 4 weeks.

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Figure 1. Hairs over the rump are clumped together and have adherent whitish scale at the base.

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Images of another puppy I examined with the identical presentation in 1980 appear in the 6th edition of Muller & Kirk's Small Animal Dermatology (Figs. 14-2 and 14-3).[1] This puppy was a healthy 5-week-old female, mixed breed (Figure 2) whose three littermates were unaffected. No diagnostic investigations or treatments were performed, and the condition spontaneously resolved by the time the puppy reached 3 months of age.

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Figure 2. Clumped hairs and whitish scale are present over the rump.

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To my knowledge, the only reference to this canine dermatosis appears in the classic textbook of Král and Schwartzman,[2] wherein it is likened to ‘cradle cap’ in human infants. However, the human condition appears to be different.[3] Adherent, yellow-brown, greasy scales, crusts and inflammation are present on the scalp. In puppies, greasy adherent scale crust and macroscopic inflammation are not present and the rump is predominantly affected. Histopathological findings in skin biopsies taken from infants include spongiotic dermatitis with folliculocentric scale crust. Histopathological findings in affected puppies have not been reported. The conditions are benign and self-limited in both species.

In puppies, the presentation evokes a differential diagnosis of contact dermatitis (chemical or thermal), cheyletiellosis and pediculosis. However, no history of a contactant is gathered, no ectoparasites are found, the owners have not witnessed a prior dermatitis, and spontaneous resolution is the rule. The most useful tests that might lead us to a better understanding of this condition would be skin biopsies (for histopathology) and bacterial/fungal cultures of early lesions. It will be difficult to convince the owners of otherwise healthy puppies with a spontaneously resolving condition to subject their pets to such interventions.

The prevalence of canine ‘cradle cap’ is unknown. I suspect that it is not rare, because veterinarians and dog breeders I have spoken with over the years are aware of the condition. Perhaps other colleagues will share their comments about and experiences with this entity. We need a better moniker than ‘cradle cap’… but I am hoping to avoid ‘idiopathic, self-limiting, dorsally restricted keratinization disorders of puppies’.

Sources of Funding

This study was self-funded.

Conflict of Interest

No conflicts of interest have been declared.

References

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  • 1
    Scott DW, Miller WH Jr, Griffin CE. Muller & Kirk's Small Animal Dermatology, 6th edition. Philadelphia: W.B. Saunders Co., 2001; 1003.
  • 2
    Král F, Schwartzman RM. Veterinary and Comparative Dermatology. Philadelphia: J.B. Lippincott, 1965; 175.
  • 3
    Collins CD, Hivnor C. Seborrheic dermatitis. In: Goldsmith LA, Katz SI, Gilchrist BA et al. eds. Fitzpatrick's Dermatology in General Medicine, 8th edition. New York: McGraw-Hill, 2012; 259266.