Flea Allergy Dermatitis in Cats

By Charles Hopkins Published 05/27/2007 | Pets and Animals

Fleas are by far the most common external parasites cat owners may have to deal with. Fleas are not only extremely annoying to your cat, causing discomfort and irritation; they can also cause anemia in heavily infested kittens, pass on tapeworms (Dypilidium caninum) and trigger severe allergic skin reactions in hypersensitive animals.

Feline flea allergy dermatitis (FAD) or hypersensitivity to flea saliva is on the top of the list of skin disorders seen in veterinary clinics. Cat owners are often taken by surprise when their cat is diagnosed with FAD.

"But he hasn't got any fleas!"

In allergic cats, a single fleabite can cause a hypersensitivity reaction that can persist for many days or weeks! So it's not uncommon for a cat with flea allergy to be free of fleas at the time of examination - fleas can be long time gone or there may be just one or two running around, and to find them in all that fur is not an easy task!


FAD can result in variety of skin lesions. In animals with a low degree of hypersensitivity mild skin irritation and scratching may be the only visible symptoms. Others will typically have 'miliary dermatitis', also known as feline eczema with scabs and multiple small crusty bumps (papules) with inflamed skin underneath.

These lesions are usually located at the rear end of the body, especially on the back and around the base of the tail. They can be extremely itchy and distressing for the cat. Many times hair loss can be seen with hairs typically broken off by licking. Constant licking, scratching and nibbling leads to secondary skin irritation and self-mutilation.

In some cases, flea allergy can present as one or two raised red-raw linear or circular lesions referred to as eosinophilic plaque or granuloma.


1. If your cat shows any signs of skin problems, have him checked over by your veterinarian. There are number of diseases which can have very similar clinical manifestations, for example food allergy, atopic dermatitis and some auto-immune disorders.

If the skin inflammation and self-trauma is severe, your vet may need to treat the cat with anti-inflammatory drugs (usually corticosteroids) to stop irritation and prevent further skin damage.

2. Treat your cat PLUS all in-contact pets with an insecticidal product which kills adult fleas and preferably also has a residual action (stays on the body for a longer period killing any new fleas jumping on animal). New generation insecticides such as Frontline (fipronil), Stronghold (selamectin) and Advantage (imidacloprid) are safe, efficient and easy to apply. Older products containing pyrethroids are less suitable for cats due to their potential toxicity.

Cats with flea allergy should be treated at regular intervals, usually once a month to prevent any new fleabites. This is especially important if your cat or any other in-contact pets have access to outdoor environment.

3. Equally important is to treat your house. Flea products applied on pets will only kill the adult fleas, not the eggs. Eggs fall on your carpets and hatch out in new fleas if the conditions are favorable - this can take anything from 16 days to more then a year!

If you decide to treat your house yourself, you can purchase a product for environmental flea control from pet shops, supermarkets or veterinarians. You also could hire a professional service to do the house treatment for you. Although more costly, it saves you the hassle and the effect lasts longer.

NEVER use the house spray on your cat!

4. As a first aid to relieve itchy and dry skin, you can use topical remedies such as soothing Aloe Vera gel, anti-inflammatory Calendula ointment or Tee Tree oil. However, cats have tendency to lick it of their skin almost straight away. Putting a lampshade can prevent this or 'Elizabethan' collar on your cat. He may not like it but the collar will also stop him 'chewing' and further damaging his skin.

5. Give your cat a worming treatment, which is effective against tapeworms such as Drontal for cats containing praziquantel.

It is advisable to treat your cat with a suitable insecticidal flea product at regular intervals even if you don't see any creatures on him. This way you can prevent many potential problems fleas may cause.