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Getting to the root of 'crab' lice

Published:Wednesday | March 3, 2010 | 12:00 AM

A senior citizen laughed at himself recently when he related to me how he tried to treat himself when he was infested with pubic (crab) lice in the 1960s. He sat in a tub of cold water for about half-hour, thinking that he would drown the little critters. Not so.

Pubic lice are tiny parasitic insects which live in coarse body hair such as pubic hair. They may infest hair on the abdomen, chest, armpits, eyelids, beard and anal area. These six-legged, 2mm-wide animals which look like crabs, feed exclusively on blood, and cannot survive for more than a day away from the human body.

They crawl from hair to hair; luckily, cannot fly or jump like fleas, so they are passed on only by close contact with another person's body, clothing, bed sheets or towels.

Condoms cannot help

In most cases, the lice are transmitted by sexual contact (the pubic hair of one person coming in contact with that of another). This is one scenario in which the condom cannot prevent sexual transmission of a disease, since condoms do not protect the hairs which the lice target.

When towels, clothes, beds and closets are shared the lice may be transmitted from one person to another (for example from adult to child). Although this is a common route by which children get pubic lice, sexual abuse should be investigated in children who have pubic lice infestation.

Signs of lice

Pubic lice are particularly difficult to find, and remain still when they are exposed to light. However, here are some signs:

Some people do not have any signs for weeks, but most people experience intense itching especially around the penis, vagina and anus, almost immediately. The critters secrete saliva when they pierce the skin for blood. We are sensitive to the protein in their saliva and so it itches.

The lice scatter dark-brown powdery droppings on underwear.

Lice eggs:
Pubic lice eggs (nits) are brown and appear at the base of the pubic or other hair near the skin.

Very tiny specks may appear on the skin.

Preventing spread

Recently used clothing, bedding and towels should be washed in very hot water. Recent sexual partners and household contacts should be investigated and treated for pubic lice. Get a check-up for sexually transmitted infections too.


Pubic lice cannot go away without treatment. The treatment poisons the nervous system of lice causing their paralysis and death. Although shampoos, creams and lotions are available at the pharmacy without a prescription, children, pregnant women and people experiencing eyelid infestation should consult a doctor, since there may be serious side effects.

Permethrin (Nix), regarded as the safest, most effective and most pleasant treatment, is not available here. However, the second-line treatment gamma-benzene hydrochloride (Rid Cream, Lindane Lotion and Shampoo) is available. Treatment may be repeated three to seven days later to target any remaining eggs. Even after successful treatment, itching may continue for up to four weeks.

Dahlia McDaniel is a pharmacist and final year doctoral candidate in public health at the University of London; email: yourhealth@gleanerjm.com.