Tracking source of cat’s allergies can be frustrating

1/27/2013

Dear Dr. Thompson: During the summer of 2010 my Norwegian forest cat developed bumps along her spine from neck to tail. The bumps then turned into scabs. We went to her vet who said that it was an allergy, and she gave her a shot and within a week or so, everything disappeared. We had no recurrence during the summer of 2011. But this summer the bumps and scabs reappeared. Another trip to the veterinarian, another shot, and the explanation that ragweed pollen was especially bad this year, whereas she had seen few animals with the condition the year before. It’s January and she still is having bumps and scabs. Can you help?

Allergies are generally classified into seasonal and non-seasonal. Initially what you were describing sounds like a traditional seasonal allergy. Cats often respond to a cortisone-type injection. However, when the symptoms extend throughout the winter months a non-seasonal allergy must be considered.

As you might expect, non-seasonal allergies arise from something in the indoor environment or diet that triggers a year-round response. Symptoms in cats include areas of hair loss, crusts, and scabs. Many times people will never notice the cat licking or scratching. It is not unusual for allergies to progress from a seasonal problem to all year long.

Dust mites, fabrics, molds, and insects are all common indoor allergens that can afflict cats. Skin and blood tests are required to determine what items are troubling your pet. Once you have determined exactly what your cat is allergic to, injections can be formulated to desensitize his immune system. However, I warn people that you are treating next year’s allergy season when you start the injections. Oral cyclosporine is another option that can be effective in managing many cats’ allergies. Generally within a couple of months the symptoms are under control. Unfortunately, one of the main drawbacks with oral cyclosporine involves giving a liquid to your cat every day.

Other less common considerations would be skin parasites or ringworm. Your veterinarian can culture for ringworm and often treatment to eliminate skin parasites is needed. If your cat has an allergy to an ingredient in his diet, you will need to try feeding special protein and carbohydrate sources. This is a frustrating series of trial and error, but it is the one allergy that can be cured if you determine the offending dietary item.

This also means no treats or people food during the trial period. This can be a frustrating time while you are trying to sort out your cat’s allergies, so be patient and understand that if this truly is a non-seasonal allergy repeated steroid injections are not the long-term solution.

Questions for Dr. Gary Thompson can be emailed to askthevet@theblade.com or mailed to The Blade, Attn. Ask the Vet, 541 North Superior St., Toledo, OH 43660. Dr. Thompson regrets that he cannot answer individual letters.