Lice are small, crawling insects that infest and feed on human hosts. Contrary to earlier speculation, the presence of lice does not indication a lack of good personal hygiene. Lice are spread through person-to-person contact, and if one member of a household becomes infested, lice can spread rapidly throughout the entire family. All types of lice can usually be controlled with over-the-counter treatments, but occasionally a prescription medication may be required.
Three types of lice infest human hosts, including head lice, body lice and pubic lice, which are sometimes referred to as crabs. Head lice only live on the heads and necks of human hosts. Pubic lice typically live on the coarse hairs of the pubic region but may also infest the coarse hairs under the arms, on the chest or on facial hair such as the eyebrows or beard. Body lice don’t live on the body at all, but live in clothing and bedding. Body lice only move to the body to feed.
Body lice are the only type of lice known to spread disease, but that doesn’t mean head lice and public lice are benign. All types of lice bite and feed on human blood, causing intense itching at the site of the bite. Lice can also cause an uncomfortable tickling sensation as they move around. Lice are only spread through close personal contact. They cannot live on household pets and are not spread by contact with dogs or cats.
Two types of over-the-counter medications are approved by the U.S. Food and Drug Adminstration for the treatment of lice, including products containing pyrethrin and products containing Permethrin, which is a synthetic version of pyrethrin. Both types of products are effective in killing adult lice, but neither will kill the nits, or lice eggs. Retreatment is usually required after nine days to kill any new lice that have hatched since the original treatment. Brand name products containing pyrethrin include Rid, R&C and Triple X. Brand name products containing Permethrin include Nix. Products containing Permethrin are not approved by the FDA for treating children who are under 2 years of age.
Three types of prescription medications are approved by the FDA for treating lice, according to the U.S. Centers for Disease Control and Prevention. Malathion lotion, marketed under the brand name Ovide, can kill adult lice and some lice eggs. It is not recommended for use on children under the age of 6 years. Benzyl alcohol lotion, marketed under the brand name Ulesfia lotion, is effective in killing adult lice but will not kill the eggs. It is recommended for use on individuals who are six months and older. Lindane shampoo is approved by the FDA for lice treatment, but the American Academy of Pediatrics does not recommend its use on children. The CDC recommends Lindane shampoo only for patients who can’t tolerate other types of treatments or who have tried other types of treatments without success.
Lice can spread rapidly, particularly among people who live, work or study in close quarters. Individuals who share hats, scarves, combs, clothing, bedding towels and other personal belongings can spread lice. Individuals who come into direct personal contact can spread lice. The spread of body lice can be curtailed by regular bathing, changing clothing and laundering clothing and bedding in hot water. Parents should train their children to avoid sharing clothing, hair ornaments or tools such as combs and brushes to prevent the spread of head lice. Pubic lice can be spread through sexual contact with an infested partner. Condoms will not prevent the spread of pubic lice.