Psychogenic alopecia in cats is a condition involving self-trauma with no apparent cause. In this case series, 21 cats with a presumptive diagnosis of psychogenic alopecia were exhaustively evaluated for an underlying medical cause. A thorough behavioral history and a careful dermatologic and medical evaluation were obtained. All of the cats had the same diagnostic testing, including skin scrapings, fungal hair culture, complete blood counts, serum biochemistry panels, thyroid hormone concentrations, fecal flotation, FeLV and FIV testing, skin biopsies and histologic examination of tissues, responses to parasiticidal agents, and a food trial. Cats that did not respond to the food trial were treated with injectable DepoMedrol to determine whether pruritus was a factor. In the 21 cats, 16 of 21 were diagnosed with a medical cause for the pruritus and 11 of 16 had multiple causes. Adverse food reactions were found in 12 of the 21 cats. In the remaining 5 cats, 3 were diagnosed with a concurrent compulsive and medical condition (atopy, food, or atopy with food allergy) and the remaining 2 were confirmed to have behavioral disorders. In the 2 cats diagnosed with psychogenic alopecia, the disorder was confirmed by response to behavioral modifications and clomipramine therapy. Skin biopsies were obtained from all but 1 cat, and 14 had inflammatory skin patterns. All cats with histologic evidence of inflammation had a medical condition associated with pruritus. In the 6 cats with no inflammatory skin patterns, 2 had a compulsive disorder and 4 had food allergies or atopy and concurrent food allergies. The cat in which a biopsy could not be obtained was diagnosed with flea allergy dermatitis, food allergy, and atopy; the owner declined sedation for the cat to have a skin biopsy. Study funded by Eli Lily & Company. Donations included DepoMedrol (Pfizer Animal Health), Feline z/d low allergen diet (Hill's Pet Nutrition Inc), and Revolution (Pfizer Animal Health).
COMMENTARY: This article has 4 clear take-home messages: 1) psychogenic alopecia is rare and overdiagnosed; 2) food allergies alone or combined with other skin diseases commonly present with "psychogenic patterns"; 3) a skin biopsy with inflammatory findings in a cat with hair loss is a red flag for an undiagnosed medical condition; and 4) flea control should be performed on all pets in the home prior to investing in expensive and/or time-consuming diagnostics. Food allergies are difficult to pursue in cats for several reasons. First, other potentially pruritic causes of skin disease need to be ruled out or treated first. Second, finding a palatable food for a cat can be problematic. Third, food trials in multicat households can be cost prohibitive because the easiest way to do them is to feed all cats the same diet.
Underlying medical conditions in cats with presumptive psychogenic alopecia. Waisglass SE, Landsberg GM, Yager JA, Hall JA. JAVMA 228:1705-1709, 2006.