The Facts of Lice - Overview
What are head lice?
Head lice are small insects that live on the human scalp, feeding on human blood several times a day. These parasites make small bites in the scalp to suck blood and live off of human hosts. The bites do not hurt, but lice excrete a substance to prevent the blood from clotting, which can cause severe itching and allergic reactions. Without a host to feed on, lice will die within 1–2 days.
Who gets head lice?
Head lice are found worldwide and can infest any human. In the United States, infestation with head lice is most common among children 3-11 years old. Lice are most often found on children attending child care, preschool, and elementary school. Lice are also often transferred to the household members of infested children. The Centers for Disease Control and Prevention has estimated that up to 12 million children in the U.S. aged three to twelve are infested with head lice each year.
How do lice get into the hair?
- Head lice move by crawling; they cannot hop or fly.
- Head-to-head contact with a person who has head lice is the most common way to transfer lice. Head-to-head contact is common during play at school, at home, at the playground, at camp, at slumber parties, and during sports activities.
- Head lice may also be spread by sharing clothing items. Lice or eggs may have crawled or fallen onto items such as hats, scarves, coats, sports uniforms, helmets, hair ribbons, barrettes, combs, brushes, towels, stuffed animals, pillows, and bedding--to name a few.
- Head lice may also be spread on furniture and other household items such as beds, couches, chairs, and pillows.
- Dogs, cats, and other pets do not play a role in the spread of human lice.