[From Tufts September 2011 Issue]
I really hope that you can help us to help our cat. Our veterinarian doesn’t know what else to try. My cat licks and bites constantly, and has licked the fur off her abdomen in spots, off all four legs in spots and various other places.
Our veterinarian first administered an allergy injection and it seemed to work. However, she developed a severe reaction after receiving the second allergy shot. We then tried putting her on amitryptiline — placed on the inside of her ear —but that didn’t work.
Our veterinarian then placed our cat on a specialty dry food that also did not curb her excessive licking behavior. I feel so sorry for our cat. Any suggestions would really be appreciated. She is 7 years old, and has been doing this for about a year.
Dear Evelyn: There are many potential reasons why cats over groom and lick all the fur off their abdomens and other parts of their body. Some cats do this because of stress and anxiety. In most cases, however, cats lick excessively because the skin is itchy.
In my experience, the most common causes for this kind of behavior are some kind of allergy. Flea allergy, food allergy and atopy (allergy to inhaled allergens in the environment) are the top three allergies in cats. Flea allergy is easy enough to diagnose, so I suspect that this is not the problem with your cat. Food allergy is diagnosed by feeding a hypoallergenic diet. This is a diet that contains a protein and carbohydrate source that your cat has never encountered. I suspect that the “special dry food” that you fed (but that didn’t help) was a hypoallergenic diet. These diets need to be fed exclusively for at least 12 weeks before any conclusions can really be made.
To definitively diagnose atopy — the third common cause of allergies in cats — your cat would need to undergo intradermal skin testing at a board-certified veterinary dermatologist’s office. Some veterinarians, however, will prescribe corticosteroids and back their way into a diagnosis by evaluating the response. Food allergy usually responds poorly to corticosteroids. Atopy usually responds dramatically. The fact that the first injection seemed to work makes me suspect that atopy is a likely cause of your cat’s problem. You didn’t say the nature of the “severe reaction” that she experienced with the second injection. Corticosteroid injections, while often effective in controlling atopy, have the potential for side effects, including suppression of the immune system and possibly inducing diabetes.
Since your veterinarian doesn’t know what else to try, I think it’s time to take your cat to a board-certified veterinary dermatologist. To diagnose atopy, the dermatologist can perform intradermal skin testing and determine which environmental allergens your cat is allergic to, and then prepare a vaccine that can help desensitize your cat to the allergens, as well as perform other tests that may be warranted (such as skin scraping, skin cytology, fungal culture and skin biopsy).
If taking your cat to a veterinary dermatologist is not possible, you may want to discuss other ways to help control the itch, including using antihistamines, omega-3 fatty acids and anti-itch shampoos. I wish you good luck.
Arnold Plotnick, DVM, DACVIM