Pubic lice (Pediculosis pubis) are tiny sexually transmitted parasites. Known colloquially as “crabs” due to their crab-like appearance, they are one of three species of louse that live on human blood, along with the head louse and the body louse.
Pubic lice have the distinction-good for them, not so good for us-of being the single most contagious STD (sexually transmitted disease). It is estimated that if an uninfected person has sex once with an infected person, 90% of the time the lice will infect the uninfected person.
Because of this easy transmission, pubic lice are one of the most common of STDs, with an estimated three million new cases per year in the United States alone.
Pubic lice can infest any part of the body where there is hair, but they are found most commonly in the pubic hair, hence the name. They are exclusively external parasites, living on the surface of the skin and biting, rather than burrowing into the body. They lay their eggs down at the roots of the hair as well, so left untreated they can plague you for multiple generations.
The lice and their eggs are visible, but barely. The eggs can be mistaken for tiny flecks of dandruff, though they don’t brush off easily like dandruff. The lice are whitish-gray, and the even smaller eggs are pearl-colored and oval-shaped. You may also see red and scaly areas of skin or tiny blue bite marks where there is an infestation of pubic lice.
The worst thing about pubic lice is the itching, which can be quite severe.
Pubic lice cannot live long off the body, so transmission by way of bedding, towels, clothing, etc. is possible but not easy. The vast majority of the time they are transmitted sexually.
Unlike viral STDs, parasitic STDs can be cured, simply by killing the parasite. The usual treatment is to spread an over-the-counter lotion containing the chemical topical pesticide permethrin (the active ingredient in such products as Rid and Nix) on the affected area, letting it stand for a certain number of minutes, and then washing it off. You then take a fine-tooth comb and remove the hopefully weakened or dead lice and eggs as best you can, repeating as necessary. Better yet, shave the area entirely.
If this treatment fails, there are stronger lotions that your doctor can prescribe.
Any clothes, bedding, etc. that has had no human contact for even as little as 72 hours should be fine, as the lice cannot survive that long away from the body. But you can also eliminate them from such items by dry cleaning them, or thoroughly laundering them in hot water and drying them at high heat.
“Crabs (Pubic Lice).” STD-gov.org.
“Parasitic & Fungal Diseases.” About.com.
“Pubic lice (crabs).” Mayo Clinic.