Symptoms & Treatments for Allergies to Fleas in Cats

If your cat is itching, then it's time to check for fleas.
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When a cat incessantly licks or scratches, he may be suffering from something more than just a flea infestation. It could be that he is also suffering from an allergic reaction to the fleas. Also known as flea allergy dermatitis (FAD), this condition is irritating, yet common and treatable.


Flea allergy dermatitis typically involves excessive scratching and/or licking of the affected area and is most commonly found on the back of the cat or at the base of his tail. In fact, the cat can scratch or lick the area so much that the hair at the site can often become very thin or wear away entirely. Small raised bumps, or papules, may be noticeable on the surface of the skin or there may be clusters of tiny red scabs on the site. The skin around the affected area will also look red and irritated.

Testing for FAD

In some cases, a cat who is allergic to fleas may be suffering from an allergic reaction, yet when you check him for signs of fleas, you don't find any. This can often result in a misdiagnosis, when in truth, the absence of fleas is caused by the cat's excessive grooming. If your cat is showing signs of a flea allergy but you don't find any signs of fleas on him, take him to the veterinarian for an intradermal skin test for confirmation of FAD.


Veterinarians treat flea allergy dermatitis in a number of ways, but treatment always begins with elimination of the flea infestation. After the fleas are gone, the veterinarian may inject anti-inflammatory medication, antihistamines or steroids at the site to help reduce the swelling, itching and irritation. Topical steroid ointment may also be prescribed for continued relief and if the skin was broken by excessive scratching or biting, then a course of antibiotics is also usually prescribed.


The most effective way to prevent your sensitive-skin cat from experiencing an allergic reaction to fleas is to limit his exposure to the little pests. You can accomplish this by applying a high quality flea control product at recommended intervals on his body and by making sure he stays primarily indoors. In some cases, a veterinarian may try to desensitize the cat to fleas by injecting a tiny amount of flea antigen into the cat. This helps reprogram the cat's immune system so that it resolves the allergy naturally.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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