A cat flea allergy, also known as flea allergic dermatitis or FAD, is the most common allergy in dogs and cats. A normal, non-allergic pet will not experience more than mild itching even if exposed to dozens of cat fleas. However, in a dog or cat that is allergic to the bite of a flea, one encounter with a single flea is enough to initiate severe itching and potential secondary infections.
Dogs and cats that are allergic to fleas have an immune system that overacts to antigens which it has been exposed to. The immune system is basically attacking foreign substances that would typically be ignored. This overreaction leads to the symptoms seen in FAD. Scientists have found 15 potential antigens that can cause this type of an allergic response.
Pets that are allergic to fleas will typically itch and bite at the hair on top of the rump and tail. It is common for hair loss to occur as a result of the excessive scratching and grooming. Additionally, trauma to the skin often results in secondary bacterial infections which also must be treated. It is important to note that many dogs and cats with FAD will have very few, if any cat fleas found on them. The excessive grooming often causes the pet to eat any fleas on its body.
Typically, cat flea allergies are a seasonal disease which is worse in warmer months that correspond with the flea life cycle. There are other types of allergies and diseases that can cause pets to have excessive itching. Diagnosing cat flea allergies should be done by a veterinarian.
Treatment for cat flea allergies must include a rigorous flea control program. An adulticide and insect growth regulator must be consistently used. Avoidance of areas with high levels of fleas, such as dog parks, should be avoided during peak flea seasons. Relief may be obtained short term with a prescription of steroids, which blocks the reaction process. For some pets that are in warmer year-round cat flea areas, desensitization could be used for long term treatment. This involves injecting tiny amount of cat flea antigen into the pet for a prolonged period to train the immune system not to react to a cat flea bite.