The leading cause of skin problems in dogs and cats is the ordinary flea.
Fleas can occur year round in warm climates or on any pet that lives indoors.
Adult fleas survive by feeding on blood. The preferred host for this meal is your dog and cat, but in heavy infestations, fleas will readily bite humans. Most dogs and cats that are bitten by fleas will have some itching, but some pets develop a severe allergic skin condition called flea allergy dermatitis. Heavy flea infestations can cause severe anemia and even death. Fleas also carry dog and cat tapeworms.