Flea Allergy Dermatitis in Cats

If your cat is itchy, it could be fleas


Think: itchy! That is how your cat feels with flea allergy dermatitis. Flea allergy dermatitis is the most common allergy in cats and is caused by flea bites; more specifically, flea spit (yes, spit). A flea’s saliva causes your cat to become very itchy and often puts them at risk for secondary skin infections.

The vile flea
It doesn’t take many fleas to cause your cat to go into a scratching and grooming frenzy. In fact, sometimes you won’t see ANY fleas at all because cats groom themselves so much, removing the telltale signs of fleas.

Any cat can become allergic to the bites of fleas. 

If your cat is plagued with flea allergies, you may see the following symptoms:

  • Scratching of self, sometimes intensely 
  • Chewing and biting at the tail, hind end, and legs (most often, the hind legs)
  • Open, oozing sores
  • Skin damage due to scratching/licking


While flea allergy dermatitis is the most common allergy in cats, other disorders can cause similar symptoms. Your veterinary staff may recommend tests to rule out other common problems. They will take a thorough history of your cat’s behavior and symptoms and perform a thorough physical exam. Your veterinarian will most likely use a “flea comb” to look for the signs of fleas, including the fleas themselves and flea “dirt,” which is actually flea waste. If fleas are present, they may recommend controlling the flea problem as a first step to determining why your cat is so itchy. If fleas are not apparent, they may recommend tests to rule out other causes, such as food allergies, mange, mites, or ear infections. Additionally, they will recommend treatment for any secondary issues that have resulted from your cat’s intense scratching, such as wounds or open sores. 


There are two important components to treating a cat for flea allergies. The first is to control the fleas and prevent your furry friend from future bites. Your veterinarian can recommend an aggressive but, more important, safe flea control for your cat and his environment.

Your veterinarian will also treat any secondary infections that have resulted from the flea allergy. Treatment often includes antibiotics and medications to help control the itch. Getting the itch under control is key!


The best way to prevent flea allergy dermatitis is to prevent your cat from getting fleas! Talk to your veterinarian about a safe and effective form of flea prevention for your cat.

If you have any questions or concerns, you should always visit or call your veterinarian – they are your best resource to ensure the health and well-being of your pets.


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Reviewed on: 
Tuesday, June 1, 2021