Fleas are tiny insects that live off the blood of their host. They have no wings but posses tremendous jumping ability, able to jump two hundred times there body length. There bodies have also adapted over time to withstand great pressure as you can see demonstrated when you try to squeeze a flea between your fingers only to see them jump away. The female flea will lay up to 500 eggs in her lifetime, so the numbers of fleas on your pets and around your home can quickly get out of hand.
Dogs will bite and scratch themselves in an attempt to remove these feasting parasites. However, the appetite of a flea is not restricted to just dogs. Other mammals, birds, and even humans can become a host. Yet the problems with fleas goes beyond the skin irritation. Fleas can transmit a variety of viral and bacterial diseases, and have even been associated with epidemics such as the bubonic plague by spreading it from rodents to humans.
Anti-itch creams, such as calamine lotion, can be used to treat flea bites in humans. Dogs, however, require a flea medication such as Advantage, Advantix, and Frontline. Treatment, however, goes beyond just treating the host. The environment also needs to be taken care of. Frequent vacuuming will help, but you must dispose of the bag immediately afterwards. For real bad infestations you may have to consider using a fogger in the home.