Head lice are parasitic wingless insects. They live on people's heads and feed on their blood. An adult louse is about the size of a sesame seed. The eggs, called nits, are even smaller - about the size of a knot in thread. Lice and nits are found on or near the scalp, most often at the neckline and behind the ears.
Lice spread by close person-to-person contact. It is possible, but not common, to get lice by sharing personal belongings such as hats or hairbrushes. Children ages 3-11 and their families get head lice most often. Personal hygiene has nothing to do with getting head lice. Head lice do not spread disease.
- Tickling feeling in the hair
- Frequent itching
- Sores from scratching
- Irritability and difficulty sleeping. Head lice are most active in the dark.
Treatment is recommended for people who have an active infestation of head lice. All household members and other close contacts should be checked and treated if necessary. Some experts also recommend treating anyone who shares a bed with an infested person. It is important to treat everyone at the same time.
Centers for Disease Control and Prevention
Treatments and Therapies
- Head Lice (Beyond the Basics) (UpToDate)
- Head Lice: Malathion Frequently Asked Questions (Centers for Disease Control and Prevention)
- Head Lice: Treatment (Centers for Disease Control and Prevention) Also in Spanish
- Head Lice: Treatment Frequently Asked Questions (FAQs) (Centers for Disease Control and Prevention) Also in Spanish
- ClinicalTrials.gov: Head Lice (National Institutes of Health)