Related topics: •  Chlamydia •  Gonorrhea •  HPV and Genital Warts •  Herpes •  Scabies •  Syphilis

Crabs are a type of louse that typically infests the hair in the pubic area, where it causes intense itching. The problem begins when a female crab louse lays egg sacs (or nits) at the bases of your pubic hairs. In 5 to 10 days the eggs hatch, and a few weeks later each louse is strong enough to dig its way into the follicle of a pubic hair and feed on tiny amounts of blood. Lice can live for 40 days after they hatch (although it might seem like more).

If you have crabs (which are also known as pubic lice), you have lots of company; an estimated 3 million people are treated for them in the United States each year.

It's usually not hard -- the chronic itching around your genitals is a giveaway. Inspect your pubic area, using a magnifying glass if necessary. Crabs are relatively immobile and easy to spot. They're about the size of a pinhead and pale gray in color, but they'll appear darker when swollen with blood. If you don't see adult lice, look closely for the gray-white oval-shaped nits, which are usually attached to the bases of pubic hairs. (It will actually look a little bit like you have dandruff in your pubic hairs, except that you can't brush the spots off.) Sometimes you'll see rust-colored specks (louse excrement) scattered throughout your pubic area as well; they can also show up on light-colored underwear.

In some cases you may feel itching and discover pubic lice not only around your genitals but also on your eyebrows, eyelashes, beard, mustache, or other body hair. In children and infants especially, crabs are often found on the eyelashes.

Most likely by having sex or skin-to-skin contact with someone who has them. It's possible, though, that you picked them up by using a towel, clothes, or bedding previously used by somebody with crabs. The lice can survive for up to 24 hours on clothing and other items that have been in close contact with an infested person. It's a common misbelief that crabs can be easily contracted from sitting on a public toilet seat. This is not impossible but very rare, since lice don't have feet designed to walk or hold onto smooth surfaces.

The pesky lice inject a substance that produces an allergic reaction on your skin, which causes you to itch. (Some people develop bluish spots from the allergy.) Your skin may also look red and blotchy, but that's probably because you've been scratching too much.

It's hard not to scratch, but try to avoid doing so. Scratching can create sores in your genital area that might get infected, and you may spread the lice to other hairy parts of the body by scratching the pubic region and then touching your eyebrows or armpits.

Pubic lice are smaller and have more compact, crablike bodies than head or body lice. They're also typically found in the pubic area, while head lice live on the scalp and body lice on the shoulders, trunk, and buttocks.

Fortunately, the cure is relatively easy and inexpensive. The treatments -- over-the-counter lotions and shampoos -- are the same as those for head lice. For years the recommended remedy was a shampoo containing lindane, but because the insecticide is highly toxic and lice are showing resistance to it, this is no longer the treatment of choice. Instead, look for permethrin or pyrethrum extracts, which are sold under such brand names as RID, Nix, and A-200. (You should avoid pyrethrum-based products if you get hay fever or have an allergy to ragweed.) Ask your doctor or pharmacist to recommend a remedy, and be careful to follow the product guidelines. If you're pregnant, you'll need to use a specially formulated product called Eurax.

A warning: Never use a dangerous home remedy like kerosene or gasoline; these substances are flammable and highly toxic.)

Even after the lice are gone, you may still feel itchy for a couple of days. It takes time for your irritated skin to heal.

•Comb them away. After using a lotion or shampoo to kill the crabs, carefully remove all nits with a nit comb, which you can buy at a drugstore or order from the National Pediculosis Association at (866) 323-5465. Some experts think that saturating your pubic hair with a vinegar-and-water solution may help loosen the glue that binds the nits to the hair and make them easier to remove.

•Check your eyelashes. If the crabs have taken up residence there, you'll need to remove as many of them and their nits as possible, then apply an ointment recommended by your physician. Many doctors advise that you smooth a thick layer of petroleum jelly onto the edges of your eyelids twice a day for 8 to 10 days; this is a nontoxic way to suffocate the lice.

•Do a giant load of laundry. Once you've treated your body to a thorough cleaning, you've got to do the same for all bedding, clothes, and other articles that might harbor the lice or nits (the eggs can live as long as six days, and the lice themselves can survive up to 24 hours without you as their host). Use hot water and a high dryer setting. Seal combs, brushes, and other items that can't be washed in the machine inside plastic bags for 10 to 14 days (this will give the nits time to hatch and -- since they'll lack a human blood source -- to die.)

•Make sure the people who are close to you get treatment too. Your sexual partner or partners, as well as anyone else with whom you've been in close contact, should be treated at the same time you are. If they aren't, you're likely to get reinfected.

Limiting the number of sexual partners you have is the best way to reduce your chances of getting them. Take these precautions as well:

•Avoid using other people's clothes or bedding.

•Wear underpants when you try on bathing suits at the store.

References

First published August 9, 1999
Last updated March 3, 2008
Copyright © 1999 Consumer Health Interactive

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