Head lice are tiny insects that live on the skin covering the top of your head (scalp). Head lice may also be found in eyebrows and eyelashes.
Lice can be spread by close contact with other people.
Head lice infect hair on the head. Tiny eggs on the hair look like flakes of dandruff. However, instead of flaking off the scalp, they stay put.
Head lice can live up to 30 days on a human. Their eggs can live for more than 2 weeks.
Head lice spread easily, particularly among school children. Head lice are more common in close, overcrowded living conditions.
You can get head lice if you:
Having head lice causes intense itching, but does not lead to serious medical problems. Unlike body lice,head lice never carry or spread diseases.
Having head lice does NOT mean the person has poor hygiene or low social status.
Head lice can be hard to see. You need to look closely. Use disposable gloves and look at the person's head under a bright light. Full sun or the brightest lights in your home during daylight hours work well. A magnifying glass can help.
To look for head lice:
Both children and adults should be treated right away if any lice or eggs are found.
Lotions and shampoos containing 1% permethrin (Nix) often work well. You can buy these medicines at the store without a prescription. If these products do not work, a doctor can give you a prescription for stronger medicine. Always use the medicines exactly as directed. Using them too often or in the wrong way can cause side effects.
To use the medicine shampoo:
When treating lice, wash all clothes and bed linens in hot water with detergent. This also helps prevent head lice from spreading to others during the short period when head lice can survive off the human body.
Ask your health care provider if people who share bedding or clothes with the person who has head lice need to be treated as well.
Most of the time, lice are killed with the proper treatment. However, lice can come back if you do not get rid of them at the source.
Some people will develop a skin infection from scratching. Antihistamines can help ease itching.
Call your health care provider if:
Never share hair brushes, combs, hair pieces, hats, bedding, towels, or clothing with someone who has head lice.
If your child has lice, be sure to check policies at schools and daycare. Many places do not allow infected children to be at school until the lice have been completely treated.
Some schools may have policies to make sure the environment is clear of lice. Cleaning of carpets and other surfaces often helps prevent spread of all types of infections, including head lice.
Pediculosis capitis - head lice
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Elston DM. Arthropods and leeches. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 367.
Diaz JH. Lice (pediculosis). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 293.
Burkhart CN, Burkhart CG, Morrell DS. Infestations. In: Bolognia JL, Jorizzo JL, Schaffer JV, et al, eds. Dermatology. 3rd ed. Philadelphia, Pa: Mosby Elsevier; 2012:chap 84.
Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang
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