Flea allergy dermatitis, or FAD, is the most common allergic skin disorder in pets. Here are the symptoms and reasons, below are the answers to help you and your pet find both instant and long-term relief!

* Fleas bite and suck blood from a host to feed themselves in the same way that a mosquito does.

* Unlike a mosquito, who eats once and goes off to digest its meal, fleas continue to bite a host animal long after their hunger is satisfied.

* They do this to produce flea droppings containing undigested blood.

* These droppings are very high in protein and iron and are eaten by the immature stage of a flea's life cycle.

* A flea bite may leave no mark at all, but it can leave instead a small, red spot surrounded by a reddened halo if the host is sensitive to its bite.

* Unless there is an allergic skin reaction, there may not be any swelling.

* But many dogs and cats develop an allergic reaction to flea saliva, occasionally producing severe skin reactions.

* In dogs, there is no preferred breed or sex for development of FAD. Most cases are observed in dogs between one and six years of age.

* Animals can be different, with different sensitivities and tolerances. It is possible to have two pets living together in the same environment and have one react violently to flea bites with severe scratching and rubbing, while the other shows little or no reaction.