This is Dr.Christian. Chewing lice are spread from other dogs (technically they can get on you but will not stay there long- they like one species only). They chew the skin for a meal rather then suck their meal like a mosquito. The lice crawl on the skin chewing and feeding. They cause itching and irritation. They also lay eggs on the hair. They look like little white specks as they crawl around on the skin. Truthfully they are pretty rare. In most cases they are found on stray or abandoned animals with poor health. If you have more questions please let me know.
I am not sure if my dog has them,,,but it is nice to know what they are and how to treat them. I hadnever heard of them before the commerical on TV.