Lice Facts - Overview

What are head lice?

Head lice are small insects that live on the human scalp, feeding on human blood several times a day. The bite these parasites make to suck blood does not hurt, but the substance the louse excretes to prevent the blood from clotting can cause itching and allergic reactions. Without these blood meals, lice will die within 1–2 days.

Who gets head lice?

Head lice are found worldwide. In the United States, infestation with head lice is most common among preschool children attending child care, elementary school children, and 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 get 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 items where lice or eggs may have crawled or fallen, including clothing (hats, scarves, coats, sports uniforms, helmets) or articles recently worn or used by an infested person (hair ribbons, barrettes, combs, brushes, towels, stuffed animals).
  • Head lice may also be spread by lying on a bed, couch, or pillow that has recently been in contact with an infested person.
  • Dogs, cats, and other pets do not play a role in the spread of human lice.

Lice Facts: Life Cycle »