Head lice are small insects, gray or white in color and have no wings. Head lice have claws that cling to hair shafts and they spend their entire life cycle on the heads of people sucking blood for nutrition.
Because head lice cannot live for more than 48 hours without a blood meal, they do not live long off the head. Head lice are usually spread by close personal contact with the hair of an infested person. Sharing personal items such as combs, brushes, towels, bedsheets, hats, coats, or storing these items close together such as in classrooms can spread lice. Itching is the most common symptom caused by an allergic reaction to the bites. Other symptoms include a tickling feeling of something moving in the hair, irritability, and sores on the head caused by scratching.