Head lice are tiny insects that live on the skin covering the top of your head, called the scalp. Lice can be spread by close contact with other people.
Head lice may also be found in eyebrows and eyelashes.
Causes, incidence, and risk factorsHead 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:
SymptomsSymptoms of head lice include:
Signs and testsHead 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.Part the hair all the way down to the scalp in very small sections, looking both for moving lice and eggs (nits). Look at the entire head this way. Look closely around the top of the neck and ears, the most common locations for eggs.Treatment is recommended if even one egg is found.
TreatmentLotions and shampoos containing 1% permethrin (Nix) often work well. They can be bought at the store without a prescription. If these do not work, a doctor can give you a prescription for stronger medicine. Such medicine should be used exactly as directed.
Expectations (prognosis)Lice are usually killed with the proper treatment. However, lice may come back, especially if the source is not corrected.
ComplicationsSome people will develop a secondary skin infection from scratching. Antihistamines can help relieve the itching.
Calling your health care providerCall your health care provider if symptoms continue after home treatment, or if you develop areas of red, tender skin, which could mean a possible infection.
PreventionNever 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, day-care centers, preschools, and nurseries. Many 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. Sometimes, the insects or their eggs get into areas such as carpets. Frequent cleaning of carpets and all other surfaces in child-care centers prevents spread of all types of infections, including head lice.