Small Animal Dermatology Q&A 08

This question was provided by Manson Publishing as part of the OVAL Project. See more small animal dermatological questions

A 10-week-old chow chow puppy is presented for hair loss, erythema, itching behind the right ear, and on the right rear foot. An area of ulceration on the digit is also present, and the owner reported the wound was self-inflicted. Upon questioning, the owner reports that the lesions slowly developed over 2 weeks, and that hair loss preceded pruritus.

Question	Answer		Article
What are the differential diagnoses, and what diagnostic tests are indicated?	This puppy has two major dermatological problems: pruritus and hair loss. The most common causes of hair loss in puppies are demodicosis, dermatophytosis, and bacterial pyoderma. The most common causes of pruritus include flea infestation, demodicosis, scabies, cheyletiellosis, dermatophytosis, and bacterial pyoderma. The diagnostics tests indicated are deep skin scrapings for demodicosis, impressions smears to look for yeast and/or cocci, and a dermatophyte culture. This is a case of dermatophytosis due to Microsporum gypseum. The puppy contracted this dermatophyte while at the breeder’s home since several other littermates and the bitch also developed lesions. The puppies were also housed outside in a pen with a dirt floor. M. gypseum is a geophilic organism, and animals contract it from exposure to contaminated soil, often through digging. This puppy was treated successfully with topical lime sulfur dips twice a week, for 8 weeks. The puppy was treated until two negative fungal cultures were obtained at 2 week intervals. Systemic antifungal therapy was not used in this puppy because it was <12 weeks of age. It is also important to inform the owner that this is a zoonotic disease.		Link to Article
Closer examination of the skin revealed that follicular plugging caused hyperpigmentation in this patient. What skin diseases are associated with follicular plugging?	Follicular plugging with black debris is common in demodicosis, Malassezia dermatitis, bacterial pyoderma, and seborrheic skin diseases.		Link to Article