It also occurs in cats but does not appear as widespread or common.
Fleas hop onto their hosts and pierce the skin to ingest a blood meal.
Flea saliva contains enzymes and histamine-like substances which cause allergic reactions. These allergens circulate through the blood where antibodies develop in response. Symptoms of FAD in dogs include excessive itching and discomfort. Commonly affected areas include the rump around the tail, down the thighs and on the stomach. Other areas such as the ears and neck can also be affected.