Lice are very small insects that feed on human blood. The female louse attaches her eggs (nits) to the base of the hair near the scalp, and the nits hatch 7–10 days later. While the adult louse cannot survive for more than 2 days off the human head, a nit can stay alive for up to 10 days off the body (for example, on clothes, hairbrushes, or carpets). Lice are spread from child to child by close head-to-head contact and by sharing belongings that are infested with lice.
Small red bumps or sores may be seen on the scalp, neck, and shoulders. Occasionally, the lymph nodes behind the ears or in the neck may be swollen and tender. Lice may sometimes be seen on the eyelashes, causing the eyes to become red and irritated.
Because head lice infestations are quite itchy, scratching is common and may lead to resultant infection or scabbing. In addition to an itching or tickling sensation, children may also be irritable or have difficulty sleeping.
If you find lice and/or nits, follow these guidelines:
- Over-the-counter medications for head lice are effective and should be the first treatment you use. These include pyrethrins (A200®, Pronto®, R&C®, RID®, Triple X®) and permethrin lotion 1% (Nix®). Both medicines kill only live lice, not the eggs, so they should be reapplied in 7–10 days to kill newly hatched lice. These treatments are only minimally absorbed through the skin, but they should not be used on children aged younger than 2 years. Use these medicines exactly as directed. These medicines are insecticides and should not be applied in greater quantity or more frequently than recommended.
- Before applying the over-the-counter lotions, do not use conditioner on the hair, as this will coat the hair and protect the lice from the medicine. Also, do not wash the hair for 1–2 days after treatment.
- After the treatment, wear clean clothes and wash other clothes, bed linens, and towels in hot water (greater than 130°F [54.45°C]) and dry them using the hot cycle for at least 20 minutes.
- Wash any object that your child has come into contact with during the past 48 hours in hot water for at least 5 minutes.
- Seal potentially contaminated but nonwashable objects in plastic bags for 2 weeks. (The lice will die within 2 days, and the nits will hatch and die within 2 weeks.)
- Vacuum floors and furniture.
- Examine the hair and scalp of household members and treat them if they are infested.
- Notify the school nurse, teacher, or day-care provider if your child is diagnosed with head lice. Your child can return to school after proper treatment.
- Do not share combs, hairbrushes, hats, towels, bedding, clothing, headphones, stuffed toys, or other items with someone who has head lice.
If the doctor confirms that your child does have lice and you have not yet treated the infestation, he/she will likely recommend over-the-counter medications as described in the Self-Care Guidelines section. If you have already used over-the-counter medications and you still see moving lice, your doctor will probably give you a prescription-strength medication. These include the following:
- Malathion lotion 0.5% (Ovide®) – Kills lice and some eggs and can be used only on children aged older than 6 years. Malathion can irritate the skin and is flammable. It can be absorbed into the skin, especially if it is left on the skin for a long time, so follow the application directions exactly.
- Lindane shampoo 1% – This can be toxic and is absorbed into the blood stream and, therefore, is not used much anymore it. This medication is used only when other medications have failed.
- Ivermectin pills – This oral medication is passed to the lice when they eat human blood. Again, this is used only when other medicines have failed.
Bolognia, Jean L., ed. Dermatology, pp.1324-1326. New York: Mosby, 2003.
Centers for Disease Control and Prevention. Head Lice. http://www.cdc.gov/lice/head/index.html. Modified May 16, 2008. Accessed online March 9, 2009.
Freedberg, Irwin M., ed. Fitzpatrick's Dermatology in General Medicine. 6th ed. pp.2286-2288. New York: McGraw-Hill, 2003.
Stone SP, Goldfarb JN, Bacelieri RE. Scabies, other mites, and Pediculosis. Wolff K, Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, eds. Fitzpatrick's Dermatology in General Medicine. 7th ed. New York, NY: McGraw-Hill; 2008:2029-2037.