Vet360, December 2016 - Page 12

DERMATOLOGY Article reprinted with the permission of Advanstar. The article was originally printed in VETTED June, 2016. VETTED is a copyrighted publication of Advanstar Communications inc. All rights reserved. Shaping the future of animal health The Idiosyncrasies of Itchy Cats Heather Lewellen, DVM As discussed with: Rudyana Ghubash DVM DACVD) Cats are not small dogs; we’ve heard that before. It’s never quite so true in veterinary medicine as for a dermatologist! “Cats don’t do things that dogs do,” says Rudayna Ghubash, DVM, DACVD, Animal Dermatology Clinic in Marina del Rey, California. “You can’t base your dermatologic differential list on what part of the body is affected by evidence of pruritus like you can with dogs.” Just because a cat is itchy on its head and neck, doesn’t mean that the underlying cause is a food allergy. In Dr. Ghubash’s experience, head and neck pruritus are usually involved in atopy and food allergy, but not always! So what is the answer for felines? Dr. Ghubash reiterates that because cats’ physiologic response to allergenic opportunities are so different from dogs’, it takes a different approach to diagnosing what’s causing the clinical signs. Physical examination pointers Pay attention to a patterns of lesions. Are there excoriations present indicating trauma? Are there milia indicative of miliary dermatitis, commonly a sign of allergic disease? Check the lips and palates for eosinophilic granuloma complex lesions. Treating secondary infections you identify is paramount. It’s not wrong to start with administering antibiotics alone for a week or two and if you’re not making any progress in clinical signs, then use corticosteroids. Dr. Ghubash’s recommended approach to a cat presented to you for pruritus is to start with a careful and deliberate history and to examine each pruritic cat in a vet360 Issue 06 | DECEMBER 2016 | 12 methodical way. She estimates that about 50% of your valuable information will come from the signalment and history, if you ask the client the right questions. For example, a cat younger than 6 months old is more likely to have an underlying parasite or dermatophyte causing its pruritus. Atopy is rare in kittens that young.  A complete history-taking of the cat’s previous and concurrent disease is very important. For example, cats don’t get pododermatitis from allergies like dogs do. If they get it, the underlying cause is more likely to be pemphigus foliaceus. They tend to get more of the “shake and bake” appearance of ear crusts. Particulars on pruritic predicaments in cats Dermatophytosis Explore dermatophytosis in your patients first because it can mimic any other dermatologic disease, pruritic or not. Always recommend performing a dermatophyte test medium (DTM) culture. Keep in mind that Wood’s lamp examinations are only accurate about 50% of the time. If you’ve taken a biopsy, you should request periodic acid-Schiff (PAS) and Gomori’s methenamine silver (GMS) stains if you’re concerned about dermatophytes. Quick tip: In young Persian cats with dermatologic ailments, dermatophytosis should be at the top of the differential diagnosis list until proven otherwise by diagnostics, the gold standard currently being dermatophyte culture.