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The Daily Vet by petMD

The Daily Vet is a blog featuring veterinarians from all walks of life. Every week they will tackle entertaining, interesting, and sometimes difficult topics in the world of animal medicine – all in the hopes that their unique insights and personal experiences will help you to understand your pets.


It’s that time of year again. Spring-time heading into summer. The fleas are out in full force. Plants are blooming. Pollen is flying. And your cat may be suffering from allergies.


In cats, allergies most commonly surface as skin problems rather than respiratory problems like they do in people. We do occasionally see respiratory symptoms due to allergies, but generally cats suffering from allergies are itchy. They may have bald spots and/or sores and scabs on their skin.


What are the most common allergies we see in cats?


Fleas top the list. Commonly known as flea allergy dermatitis, or FAD, flea allergies are extremely uncomfortable for your cat. And not seeing fleas on your cat doesn’t rule out the possibility of a flea allergy causing your cat’s skin problem either. Cats groom themselves constantly - even more so when they have allergies. Through grooming they may remove the evidence of a mild flea infestation. Plus it only takes one flea bite to set off the allergy. Just one.


Atopy is another common allergy we see in cats. Atopy is an allergy to something your cat is in contact with in his environment.


Food allergies can occur as well. Your cat can actually become allergic to an ingredient or ingredients in his diet.


How are allergies in cats best treated?


The best treatment depends on the cause of the allergy. Flea allergies are treated by eliminating the flea population. Atopy is treated by avoidance (if possible) and sometimes with other anti-inflammatory medications or "allergy shots," which hyposensitize the cat to the substances to which he is allergic. Food allergies are treated by avoiding the food ingredient that is causing the allergy.


Unfortunately, one of the problems encountered with skin allergies is that all of these allergies look exactly the same. It’s impossible to simply look at a cat and say, "That cat has a food allergy," and "That one has atopy." There are clues that can give hints as to the cause. Finding flea dirt or living fleas on a cat means that a flea infestation is present and must be treated, obviously. Skin problems that are seasonal are more likely to be atopy, or possibly flea allergies. Food allergies most often cause symptoms year round. But even these rules are not set in stone and an individual cat can suffer from more than one type of allergy as well. Some cats suffer from both flea allergies and atopy at the same time, for instance.


As a result, treatment of a skin problem often involves a multi-faceted approach. Effective flea control is almost always advisable to rule out the possibility of a flea allergy. A special diet may be recommended as a feeding trial in case of food allergies. Use of medications such as corticosteroids and cyclosporine (Atopica) are controversial but they are used by some veterinarians. Secondary skin infections may require antibiotics. (Secondary skin infections are common for cats that have allergies and are a result of the trauma to the skin caused when your cat scratches.)


Consult your veterinarian to determine the best course of action for your cat if you think your cat has allergies. Your veterinarian can help you diagnose your cat’s problem and can help you to choose a flea product that is safe and effective for your cat, a food that is suitable, and to determine what other medications, if any, may be needed.



Dr. Lorie Huston



Image: Prill / Shutterstock

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  • Cat Allergies
    05/21/2012 07:22am

    I adopted Ivy Elizabeth when she was surrendered to the vet. She had been taken to the clinic for euthanasia because the previous humans didn't want to deal with her allergies. Luckily, the vet asked if Ivy could be surrendered instead and they agreed.

    Bless her heart, she itched so badly that she groomed all her fur off from the "waist" down. She was being treated with heavy-duty steroids at the time, but it gave her very temporary relief. Luckily she didn't turn diabetic.

    Long story short, a lot of things were attempted, but nothing helped until a R.A.S.T. was done. There was only a 50% possibility this would identify her problems, but it worked! Poor little girl, she was allergic to dust, pollen, kapok, chicken and a myriad of other things. She was started on allergy injections which was a challenge because I had no experience with this as was totally paranoid she would have a reaction.

    However, it worked! After working up to the full dose, she had to have injections more frequently than once a month for keep her allergies in check, but it was well worth it. Knowing what I know now, my first stop would be the veterinary dermatologist.

    When Clara's lower lip swelled up, she was diagnosed with an eosinophlic granuloma (rodent ulcer), but with a little work, it turned out she was sleeping on my pillow and was allergic to the laundry soap. Changing laundry detergent cleared up the problem entirely.

    Critters with allergies can be a challenge, but finding the right treatment is so rewarding when you find a way to give them relief.

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