Head Lice

What are head lice?

Head lice are small, wingless insects about the size of a sesame seed. They live on the human scalp and in the hair. They have six legs and move very quickly. Head lice are parasites - they live by feeding on the blood from the human scalp. They cannot stay alive for more than two days off the human body.

Lice do not spread diseases, and so they are not a major health problem.

What are nits?

Nits are the small, oval-shaped eggs of head lice. Lice lay their eggs very close to the scalp, and the eggs hatch within a week. Nits may be tan or coffee-colored. They are hard to see until they hatch. Once they hatch, the casing (outside) of the nits is white and easier to see. Lice are harder to see than nits because they are tiny, fewer in number, and crawl quickly away from light.

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Who gets head lice?

Lice are a common problem for children, and less often for adults. Children are most likely to get lice because of the close physical contact they have with playmates in school and day care centers. Head lice are not caused by poor hygiene. Anyone can get head lice.

How are head lice spread?

Lice are spread from person to person by direct head-to-head contact, for as long as the lice are alive on the infected person. Head lice can also be spread by sharing combs, hats and other objects such as carpet, car seats and bedding. Although head lice do move quickly, they cannot fly or hop off to another person.

Unhatched eggs cannot be spread from person to person. Pets do not spread head lice.

How can you tell if someone has head lice?

One of the first signs that a person may have head lice is itching and scratching at the back of the head and around the ears. Lice and nits are hard to find unless you look closely at the hair and scalp. Unlike dandruff, the nits are firmly attached to a strand of hair.

If nits are found within half an inch of the scalp, the scalp should be treated. Nits found more than a half inch from the scalp have already hatched or been killed by treatment, and removal is not necessary.

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What if a child is sent home from school with head lice?

Schools may have a variety of policies on head lice. However, a child with active head lice is of little risk to others. If a child is found to have head lice it is recommended that he or she be allowed to stay in school until the end of the school day – but should be discouraged from having direct contact with others.

The child should be allowed to return to school after the first recommended treatment. There may still be nits left in the hair that were killed by the treatment. Re-treatment is usually recommended in 7 to 10 days.

Can you get other diseases from head lice?

Head lice do not spread diseases. Lice can, however, cause physical discomfort, anxiety, embarrassment and the cost of treatment may be a hardship. Toxic or caustic substances should not be used to treat lice.

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What is the treatment for head lice?

An over-the-counter medication such as Nix (Permethrin) or RID (Pyrethin) is recommended. Follow the directions carefully. Lice are usually killed in one treatment. However, a second treatment 7 to 10 days later is also recommended to make sure all nits are killed. Dead nits do not fall off the hair after treatment. Prescription medications are available only if your health provider recommends that one is necessary. Check everyone in the household for lice and nits. Pay special attention to the nape of the neck, behind the ears and within one inch of the scalp. Nits can be removed after treatment with a “nit comb” or with fingernails. Treat only those people in the household who have live lice or nits within half an inch of the scalp. Because over-the-counter treatments may have side effects, do not use lice treatments to try to prevent lice. Do not use the prescription medication, Kwell (Lindane) with infants, young children or pregnant or breastfeeding women.

How can you prevent the spread of head lice in your home?

To help prevent the spread of head lice, teach children not to share combs, brushes and hats. Treat anyone with active lice or unhatched eggs right away. Lice can live for less than two days off the head. Head lice do not reproduce off the body. They do not live on pets. Any nits that fall off the head will not hatch or reattach.

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Other ways to prevent lice from returning

For more information

Contact your child’s primary care provider, the school nurse, or your Department of Health district office.

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