Veterinarian-written / veterinarian-approved articles for your cat.

Flea Allergy Dermatitis in Cats

Flea allergies in cats can cause serious skin conditions.

Fleas are common parasites that bite and feed on cats. They then drop off the cat and lay eggs in the environment, which hatch into more fleas that jump onto and feed off of nearby cats and other mammals.

Problems in Cats Caused by Fleas

Many cats that are affected by fleas aren't bothered too much by them. However, there are some serious conditions that can be caused by a flea infestation on a cat. These include:

  • Anemia, or low red blood cell count. This can occur when there is an extremely high flea load or when the affected cat is young, elderly, or otherwise ill. The anemia caused by fleas can be life-threatening in certain instances.
  • Tapeworm infection. Dipylidium caninum is a type of tapeworm that uses flea larvae as intermediate hosts. When infected larvae become adult fleas and are eaten by a cat that is grooming himself, the kitty can become infected with this type of tapeworm. Learn more: "Tapeworms in Cats."
  • Feline hemotropic mycoplasmosis. Flea bites can transmit Mycoplasma haemominutum or Mycoplasma haemofelis to cats. These are bacteria that attach themselves to red blood cells. The cat's body mounts an immune attack on the bacteria but destroys the associated red blood cells at the same time. The result can be serious anemia and possibly death unless the infection is diagnosed and treated aggressively with antibiotics.
  • Bartonella henselae infection. It's possible that this bacteria may cause painful gum inflammation and other inflammatory processes in a cat's body, but scientists aren't sure about this. However, B. henselae is the causative agent of cat scratch disease in humans, and cats become infected with it through flea bites.
  • Flea allergy dermatitis. This condition occurs when a cat is allergic to flea saliva. A cat with this allergy can suffer from excessive itchiness and resultant skin damage when bitten by just a few fleas.

What Is Flea Allergy Dermatitis in Cats?

Flea allergy dermatitis in cats occurs when the kitty's immune system overreacts to flea saliva, mounting an over-the-top response to its presence in the cat's body. The histamine that is released during this response causes intensely itchy, fluid-filled bumps to appear on the cat's skin.

When they cat begins to scratch at these bumps, skin damage and subsequent infection can occur rapidly, which leads to even more skin discomfort, then more itching, and the process quickly becomes a vicious cycle.

Signs of Feline Flea Allergy Dermatitis

If your cat has some or all of the signs listed below, flea allergy dermatitis may be the culprit. These signs can all be caused by other allergies and skin conditions, so a veterinary exam and possibly some skin testing may be required for proper diagnosis.

  • Intense scratching of the skin, especially around the face, head, and neck.
  • Bumps on the skin.
  • Redness, open wounds, and oozing sores on the skin.
  • Hair loss.
  • The presence of fleas and/or flea dirt on the cat's skin. You can learn how to check for this here: "Cat Fleas: Does My Cat Have Fleas?"

Flea Allergy Dermatitis Diagnosis in Cats

Diagnosis of flea allergy dermatitis in cats is generally achieved through analyzing the cat's history of clinical signs, finding fleas on the pet, and noting a serious skin condition in association with them.

Skin testing for allergies may also be necessary to ensure there is not another cause for the cat's reaction.

Treatment of Flea Allergy Dermatitis in Cats

Treatment of flea allergy dermatitis hinges on ridding the cat's environment of fleas and preventing their reintroduction. You can learn more here, "Flea Control for Cats," but your veterinarian is best suited to help you develop an individualized flea control plan for your pets and home.

In the meantime, several treatments may be necessary to stop your cat's current allergic reaction and treat any subsequent skin inflammation and infection. These treatments may include:

  • Corticosteroid pills or injections can help control the cat's immune system overresponse.
  • Antibiotics, injectable or oral, may be necessary.
  • Antihistamines can help some cats.
  • Applying Soft Paws® to your cat's claws to decrease the damage done by scratching until the reaction can be stopped.

Never give your cat any medication without talking to your veterinarian first. Many over-the-counter, human, and pet medications are toxic to cats.

You May Also Like These Articles:

How To Clean Cat Ears

Lice in Cats

Feline Mites

Amazing Cat Facts to Know and Share

Cat Myths: Separating Fact from Fiction

Feline Acne

Ringworm in Cats

How to Remove Ticks from Cats

Disclaimer: This website is not intended to replace professional consultation, diagnosis, or treatment by a licensed veterinarian. If you require any veterinary related advice, contact your veterinarian promptly. Information at is exclusively of a general reference nature. Do not disregard veterinary advice or delay treatment as a result of accessing information at this site. Just Answer is an external service not affiliated with

Notice: Ask-a-Vet is an affiliated service for those who wish to speak with a veterinary professional about their pet's specific condition. Initially, a bot will ask questions to determine the general nature of your concern. Then, you will be transferred to a human. There is a charge for the service if you choose to connect to a veterinarian. Ask-a-Vet is not manned by the staff or owners of, and the advice given should not delay or replace a visit to your veterinarian.