What Are Lice?
Lice are small, yellowish gray, wingless insects that live on the body and feed on human blood. There are three species: head lice, pubic lice (crabs) and body lice. Head lice live on and suck blood from the scalp, leaving red spots that may itch severely. Constant scratching may lead to a secondary skin infection. The females lay small, pale, football-shaped eggs (nits) on the hair shafts close to the scalp. These eggs hatch within seven days and then usually live for several weeks. Head lice are spread through direct contact with an infested person.
Body lice live in and lay their eggs on clothing and go to the body only when they need to feed. They may transmit typhus or relapsing fever (both infectious diseases characterized by a rash and fever), although this is quite rare. Body lice usually affect people who do not change their clothes often enough. Pubic lice live in pubic hair and are usually transmitted during sexual contact. Less commonly, they may infest eyelashes, beards, armpit hair and hair around the anus.
In general, those at greatest risk for lice infestation are school children and people living in nursing homes or in other crowded or unsanitary conditions. Although lice are terribly annoying and spread quite easily, they are fairly easy to treat and rarely pose a serious health risk. Unfortunately, some head lice have become resistant to currently available over-the-counter treatment.
What Causes Lice?
- Living in an overcrowded or unhygienic environment increases the risk of lice infestation.
- Schoolchildren are often affected because of their close daily contact with schoolmates and the use of communal closets.
- Head lice can be transmitted through use of an infested hairbrush, comb, hat or set of headphones.
- Pubic lice are most often transmitted through sexual contact with an infected partner but may also be transmitted through contact with infested bedding.
Symptoms of Lice
- Intense itching, usually in hair-covered areas
- Redness and flaking of the skin
- Tiny red bite marks
- Visible lice on clothing
- Visible nits (eggs) on hair shafts
Prevention
- Check your children periodically for head lice and nits, especially during peak season (August through November).
- Do not wear the same clothes for more than a day or two. Launder clothes often.
- Bathe or shower regularly.
- Do not share pillows, combs, hairbrushes, hats or other headwear with others.
Diagnosis of Lice
- Diagnosis is usually based on self-examination. Lice and their eggs, although small, are visible on hair shafts, skin and clothes.
How to Treat Lice
- Several over-the-counter lotions and shampoos are available to treat lice. These products should be applied to all infected areas of the body (follow label instructions) and washed off. Then, using a fine-tooth comb, remove any dead lice or nits from the hair shafts. One or two more applications of the lotion may be necessary.
- Antibiotics such as Co-trimoxazole (sulfamethoxazole and trimethoprim) is sometimes prescribed as a second line treatment for head lice.
- Several shampoos are available for the treatment of head lice. Repeated use of these over several weeks is usually required.
- Combs and hairbrushes should be washed in very hot soapy water to kill any attached eggs.
- Infested clothing should be washed in very hot water and dried on a high heat cycle for at least 20 minutes.
- Items like towels, bedding, rugs, upholstery, mattresses and children’s stuffed toys should be thoroughly cleaned (or burned if necessary) to avoid reinfestation.
When to Call a Doctor
- Call a doctor if symptoms persist despite self-treatment measures.
Sources:
Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference
Simeon Margolis, M.D., Ph.D., Medical Editor
Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50
Updated by Remedy Health Media
