How do you know if fleas are causing all that itching (pruritus in veterinary terms)? Generally, unlike the burrowing, microscopic Demodex or Scabies mites, fleas can be seen scurrying along the surface of the skin.

Fleas are a dark copper color and about the size of the head of a pin. They dislike light, so your best chance of spotting fleas on a dog is to look within furry areas and on the belly and inner thighs.

"Flea dirt" can also signal that there are fleas on a dog. Flea dirt looks like dark specks of pepper scattered on the skin’s surface. If you see flea dirt—which is actually flea feces that is composed of digested blood—pick some off the pet and place on a wet paper towel. If the tiny specks spread out like a small bloodstain after a few minutes, it's definitely flea dirt, and your pet has fleas.

-PetMD

When pet owners are asked what they dread most about the summer months, the topic that invariably comes up most is fleas! 

These small, dark brown insects prefer temperatures of 60-80 degrees and humidity levels of 75-85 percent—so for most areas of the country, fleas on dogs are more than just a summer problem. In many areas of the southern United States, fleas can survive and bother your pet year-round.

Dogs often get infested with fleas through contact with other animals or contact with fleas in the environment. The strong back legs of this insect enable it to jump from host to host or from the surrounding environment onto the host. (Fleas do not have wings, so they cannot fly.)

The flea’s bite can cause itching for the host, but for a sensitive or flea-allergic animal, this itching can be quite severe. It can lead to severe scratching and chewing that causes hair loss, inflammation and secondary skin infections. Some pets can be hypersensitive to the flea's saliva and will itch all over from the bite of even a single flea.

-PetMD