A 1-year-old 66-lb (30-kg) intact male Labrador retriever was presented to the University of Wisconsin School of Veterinary Medicine's Dermatology Service for evaluation of severe pruritus and skin eruptions on its trunk and distal extremities.
The internal medicine service at the Veterinary Medical Teaching Hospital at the University of Wisconsin School of Veterinary Medicine requested a consultation on a 7-year-old intact male Boston terrier in which pituitary-dependent hyperadrenocorticism had been diagnosed one month earlier.
In my multi-specialty, referral-based veterinary hospital in the heart of San Francisco, with all our many bells and whistles, including access to numerous specialists within our clinic (internal medicine, surgeon, radiologist, dentistry, holistic, oncologist, acupuncturist and ophthalmologist), I still continue to feel very frustrated with a common skin disease: canine pyoderma.
Previously, differentials of feline facial pruritus were discussed to include ectoparasites such as flea allergy, otodectes, Notoedres and cheyletiella, food allergy, atopy including possible food storage mite allergy and demodicosis. Less common differentials include infections such as dermatophytosis, viral, and bacterial pyoderma, Malassezia dermatitis, Pemphigus foliaceus (PF) and idiopathic facial dermatitis of the Persian cat. Clinically, many of these diseases appear similar including Pemphigus foliaceus and bacterial pyoderma which can be difficult to differentiate both clinically and histopathologically.
For those nonseasonal pruritic patients where food elimination trials haven't been helpful and steroids seem to help or those patients with nonseasonal recurrent otitis or pyoderma, an allergy to house dust mites or food storage mites should be considered. Dust mites are the leading cause of allergy/asthma in humans. In dogs, it appears to exceed flea allergy as the most common intradermal skin test reaction. An estimated 30-80 percent of atopic dogs and cats skin test positive to dust mites (Photo 1). Of the two types of dust mites, Dermatophagoides farinae and Dermatophagoides pteronyssinus, cats tend to be allergic to
Test your dermatology skills on the following cases. What would you do first? Which diagnostics would yield the most information yet not break your client's wallet? Are you seeing an unusual disease or more commonly, an unusual manifestation of a common disease?
In my last article, I discussed skin diseases that result from not enough sun exposure, i.e. seasonal flank alopecia or light responsive alopecia. With the coming of summer, it is timely to offer attention to skin diseases that are exacerbated by sunlight.