Flea allergy dermatitis (FAD) is the leading cause of itching in pets. Adult fleas require a blood meal in order to reproduce, where eggs are laid in the environment. However, they do not usually remain on the dog and cat except when they are feeding. When fleas feed, they inject a small amount of saliva into the skin. Proteins in the saliva cause an intense itch response to sensitive pets. In an allergic reaction, the immune system overreacts and produces antibodies to a substance that it would normally tolerate, starting the inflammatory reaction in the skin.
Dogs and cats with flea allergy dermatitis do not have to be infested with fleas to be itchy. In fact, a single flea bite can trigger an inflammatory cycle resulting in itching for days. Pets will lick, chew, or scratch the affected sites. This results in hair loss typically extending from the middle of the back to the tail and down the rear legs. The scratching and licking can cause open sores and scabs on the skin allowing for a secondary bacterial infection to develop, which will require treatment with antibiotics and medicated shampoos as prescribed by a veterinarian. The secondary skin infection must be treated, because it will add to the itch cycle until resolved with proper treatment.
Due to the injection of flea saliva causing the allergic response, it is important to prevent fleas from biting your pet. Strict flea control is essential year round whether fleas are seen or not. Flea baths and flea collars are ineffective control for fleas, due to poor effectiveness and the high risk of toxic side effects to sensitive pets. Using an effective year round flea preventative recommended by your veterinarian will help to keep your pet and environment flea free. All pets in the household should be on an effective flea preventative including solely indoor cats, so they will not be able to harbor fleas that hitch a ride on pets that go outdoors and on our clothing. Fleas can be present year round if the climate is mild, and dormant eggs will hatch in the household as the heaters are run in the colder months. The temperatures have to be below freezing for longer than 2 consistent weeks before placing the fleas into dormancy outdoors.
Steroids are sometimes used to treat flea allergy dermatitis in the early stages of the inflammatory cycle until flea control is achieved on the pet and in the environment. While steroids relieve the itch, there are significant potential side effects to steroid use and it is not the treatment for the primary issue, fleas. The long-term use of corticosteroids can ultimately result in more harm than good to the pet. Steroids can be safely used for short-term relief of the itch; however long-term control of the flea allergy dermatitis is through year round flea preventatives.
If your pet is not currently on flea preventatives recommended by your veterinarian, please consult your veterinarian for an effective flea program.