Head lice are tiny, gray bugs. They are 2 to 3 millimeters (1/8 inch) long. They move fast and are hard to see. Head lice live in the hair and bite the scalp to suck blood.

They attach their white eggs, called nits, to the hair. Unlike dandruff, nits can’t be shaken off. The nits are easier to see than the lice because they are white and there are a lot of them.

The back of the neck is the favorite area for lice and nits. Lice and nits cause your child’s scalp to itch and have a rash.

What is the cause?

Head lice live only on human beings. They can be spread quickly by using the hat, comb, or brush of an infected person, or simply by close contact. Lice may crawl or fall onto clothing, bedding, towels, or furniture. Anyone can get lice despite good health habits and frequent hairwashing. The nits (eggs) normally hatch into lice in about 1 week.

How can I take care of my child?

  • Anti-lice shampoo or rinseUse the product your healthcare provider recommends.

    Follow the directions on the package. Most products must be used on dry hair. Pour about 2 ounces of the anti-lice shampoo into the dry hair. Add a little warm water to work up a lather. Scrub the hair and scalp for 10 minutes, by the clock. Rinse the hair thoroughly and dry it with a towel. The shampoo kills both the lice and the nits. Repeat the anti-lice shampoo once after 9 days to prevent reinfection.

  • Removing nitsOnly live lice can cause lice in other children. Nits (lice eggs) do not transmit lice.

    Most treated nits (lice eggs) are dead after the first treatment. The others will be killed with by the second treatment in 9 days.

    Removing the dead nits is not essential. However, it prevents other people from thinking that your child still has untreated lice. Nits can be removed by backcombing with a special nit comb or pulling them out individually. This is time-consuming. Wetting the hair with water makes removal easier, but avoid any products that claim they loosen the nits. (Reason: They can interfere with the ability of the anti-lice medicine to stay on the hair and keep working.)

    Nit removal is not urgent and should not interfere with the return to school. Some schools, however, have a no-nit policy and will not allow children to return if nits are visible. The American Academy of Pediatrics and the National Association of School Nurses recommend that all no-nit policies be abandoned.

  • Lice in the eyelashesIf you see any lice or nits in the eyelashes, put plain petroleum jelly on the eyelashes at bedtime for 8 days. The lice won’t survive.
  • Cleaning the houseHead lice can’t live for more than 24 hours off the human body. Nits can live for 2 weeks. Vacuum your child’s room. Soak combs and brushes for 1 hour in a solution made from the anti-lice shampoo. Wash your child’s sheets, blankets, and pillowcases in hot water. Items that can’t be washed (hats or coats) can be sealed in plastic bags for 2 weeks (until the nits are dead). You do not need to use anti-lice room sprays.
  • ContagiousnessCheck the head of everyone else living in your home. If lice or nits are seen, or they start to get an itchy scalp rash, they should be treated with anti-lice shampoo. Bedmates of children with lice should also be treated. If in doubt, have the person checked. Your child can return to school after the first treatment with the shampoo. Remind your child not to share combs and hats.

How long does it last?

After you use anti-lice shampoo twice all lice and nits should be killed. If the lice come back, it usually means your child has had contact with another infected person or you didn’t use the lice shampoo as directed. There are no lasting problems from having lice and they do not carry other diseases. A follow-up exam may be recommended 7 to 10 days after the second treatment.

When should I call my child’s healthcare provider?

Call during office hours if:

  • The rash and itching are not gone 1 week after treatment.
  • The sores start to spread or look infected.
  • The lice and nits return.
  • You have other questions or concerns.