For millions of dogs and people, the tiny flea is a relentless enemy. The flea is a small, brown, wingless insect that uses specialized mouth parts to pierce the skin and siphon blood. When a flea bites your dog, it injects a little amount of saliva into the skin to prevent blood coagulation. many animals can have fleas without showing suffering, but an unfortunate number of dogs become sensitized to this saliva. In particularly allergic animals, the bite of a single flea will cause severe itching and scratching. Fleas create the most common skin condition of dogs which is flea allergy or dermatitis.

 If your dog develops super-sensitivity to flea saliva, many changes will result.   A tiny hive can develop at the location of the fleabite, which will either heal or develop into a small red bump that eventually crusts over.  The dog may scratch and chew at himself until the area is hairless, raw and weeping serum. This can create hair loss, redness, scaling, microbial infection and high coloring of the skin.

Remember that the flea spends the most its life in the environment, not on your dog, so it can be unpleasant to find. In fact, your dog can continue to scratch without you ever seeing a flea on your pet. Check your dog carefully for fleas or for signs of flea excrement (also called flea dirt), which looks like coarsely ground pepper. When moistened, flea dirt turns a reddish brown Simply put it contains blood. If one pet in the household has fleas, assume that all dogs in the household have fleas. A single flea found on your pet probably means that there are hundreds of fleas, larva, pupa and eggs in your house.