Flea saliva is very allergenic, so a single flea can cause flea allergy dermatitis (FAD) that makes your dog itchy at the bite site (often around the head, anus, neck, tail base, or groin area). In addition to the itching/scratching, dogs with a flea infestation will deposit flea “dirt” (or digested blood in the form of their feces) on the skin. This flea dirt will appear like black pepper flakes.
Prevention: Minimize your dog’s exposure by limiting his access to locations where a heavy burden of fleas may exist — wooded areas, dog parks, daycare, kennels, etc. It is also important to utilize flea preventatives. As each pet’s needs differ, consult your veterinarian to determine which type of preventative is most appropriate (including topical, collar, or oral medication).