Pubic LiceOverview

Pubic lice, Pthirus pubis (also called 'crabs' because of their resemblance ) are one of three kinds of human lice in the large group of lice families, the others being Pediculus humanus capitis (head louse) and Pediculus humanus corporis (body louse).

Pubic lice are small, six-legged, wingless, grey parasites about 1 to 3 mm long. They can live in almost any type of human hair, but is found mainly in the pubic hair. Lice have claws on their legs that are adapted for feeding and clinging to hair or clothing. Their body shape is oval and broader than long, with four distinct lobe-like protuberances on each side of their abdomen. The pubic or crab louse is quite distinct in appearance; it has pincerlike claws resembling those of sea crabs. Lice are blood-sucking insects. They feed on human blood several times daily. They stay close to the skin for moisture, food, and warmth. They move freely and quickly, which explains their ease of transmission. A fertilized female louse lays about 10 eggs a day for up to a month until it dies. Pubic lice may be found on the short hairs of the body, areolar hair, axillary hair, beard, scalp margins, eyebrows, and eyelashes, in addition to pubic hair.

Lice infestation (pediculosis) is a common sexually-transmitted condition and is found mostly in adolescents. It is usually transmitted through sexual contact, but it can also be transmitted through physical contact with contaminated objects such as toilet seats, sheets, and blankets. Some women have acquired it while trying on swimming suits at a store. The individual louse can survive for about 24 hours apart from its necessary human host.

In the United States pediculosis affects 6-12 million people annually. Pediculosis has a worldwide distribution and is endemic both in developing and developed countries. Also it is more common in women than in men and it can affect any age group.

SIGNS AND SYMPTOMS

When the infestation consists of many adult lice the symptoms are felt immediately, but when it consists of a few lice, that then lay eggs, symptoms appear only after the eggs have hatched, which may last between two to four weeks.

The typical symptom of pediculosis is itching. Because it needs blood to survive, the louse buries its head inside a pubic hair follicle. It excretes a substance into the skin that causes the itching. Itching becomes worse at night.

Sometimes, the place where the louse bit, a red papule appears and the area may become inflated. If the infestation is left untreated, the infected individual can become sensitised. Continual scratching may lead to secondary infections and in some cases swollen lymph glands, due to bacterial infection. If the infestation involves the eyelashes, and left untreated, the eyelids can become swollen and inflamed.

TREATMENT

Pubic lice are easily treated with a 1% Permethrin or Pyrethrin lice shampoo, but the pubic hair must be shaved or combed with a fine-toothed comb to remove the nits. Wet combing or application of diluted vinegar or commercial preparations of 8% formic acid may help in the removal of nits or at least make the combing easier. Plastic or the sturdier metal nit combs may be used.

Because lice can survive apart from its human host, linen, clothing, and other materials must be disinfected. Temperature exceeding 131F (55C) for more than 5 minutes kills eggs, nymphs, and mature lice.

PREVENTION

In order to prevent a pubic lice infestation you should avoid having sex with an infected person or limit the number of your sex partners. Because pubic lice can also be contracted from bedding and towels used by an infested person it is important to avoid contact with any item that he/she has used. Also a good hygiene is very important.