Flea Allergy Dermatitis (FAD) in Cats

Flea allergy dermatitis is a hypersensitivity to flea saliva that may be caused by intermittent exposure to fleas.  A bite from a single flea will not have much effect on a normal cat, but those with FAD will react to the bite and become extremely itchy. Often the symptoms will be made much worse by the trauma the cat then inflicts upon itself.   

Symptoms of FAD

 The initial reaction to a flea bite is:

-         Redness

-         Itching, chewing, licking.

-         Inflammation

Followed by:

-         Hair loss caused by over-grooming – the skin may still look relatively normal

-         Some cats develop small red crusts on the back and rump(miliary dermatitis)

The most commonly affected areas for miliary dermatitis are the hindquarters and the area around the base of the tail. The most common areas for hair loss due to over-grooming are the inner thighs, abdomen, and flanks. 

My cat doesn’t have fleas, but she still seems to be reacting, why is this?

 This is a common scenario and usually arises because fleas are still present in your cat’s environment. Often it is very difficult to ascertain whether your cat has fleas, as cats are such good groomers they will often pick off the majority of the visible fleas. This doesn’t mean there aren’t many fleas present though, and they will be breeding and feeding the whole time that they are on the animal. Remember, one flea bite can set off the reaction. Only complete eradication of the all the life stages of fleas will stop your cat’s FAD reaction. Unfortunately there are no products available that will repel fleas, so if there are fleas in the environment, nothing will stop them from jumping onto your pet and being able to bite.

Eradication involves not only treating your cat with a good quality flea preventative, but also treating both the indoor and outdoor areas that your cat frequents with a household flea spray  that is effective against the immature life cycle stages.

If you think that your cat may be suffering from FAD we recommend that you seek the advice of your vet. They will be able to discuss with you any changes you need to make to your flea prevention regime in order to minimise the effect of flea allergy dermatitis on your cat. In more severe cases your cat may require treatment of the lesions caused by self trauma in order to get the symptoms under satisfactory control.