[1][2][3] It is usually acquired during sex, but can be spread via bedding, clothing and towels, and is more common in crowded conditions where there is close contact between people.

[5] Washing bedding and clothing in hot water kills the lice, and transmission can be prevented by avoiding sexual contact until no signs of infestation exist.

[6] Infestation with pubic lice is found in all parts of the world and occurs in all ethnic groups and all levels of society.

[1][4][8] In some infestations, a characteristic grey-blue or slate coloration macule appears (maculae caeruleae) at the feeding site, which may last for days.

[8] Scratch marks, crusting, scarring, rust-colored faecal material, blood stained underwear and secondary bacterial infection may sometimes be seen.

[1][8] Pubic lice are usually transmitted from one person to another during vaginal, oral, anal or manual sex, whether a condom is used or not.

[4][8][10] One sexual encounter with an infected person carries a high risk of catching pubic lice.

[6] Pubic lice (Pthirus pubis) have three stages: the egg (also called a nit), the nymph, and the adult.

Pubic lice nymphs take about 2–3 weeks after hatching to mature into adults capable of reproducing.

The adult pubic louse resembles a miniature crab when viewed through a strong magnifying glass.

Less commonly, hair near the anus, armpit, beard, eyebrows, moustache, and eyelashes may be involved.

[6] Brands of permethrin include 'Lyclear', available in the UK as a creme rinse or dermal cream at 5% strengths.

[17] An alternative is the combination of pyrethrins and piperonyl butoxide, in a topical application, which include the brands Licide, and A-200, Pronto and RID shampoos.

[2][4] Lindane is not recommended in pregnant and breastfeeding women, children under the age of two years, and people who have extensive dermatitis.

[4][6] The FDA warns against use in people with a history of uncontrolled seizure disorders and cautious use in infants, children, the elderly, and individuals with other skin conditions (e.g., atopic dermatitis, psoriasis) and in those who weigh less than 110 lbs (50 kg).

[22] Infestation with pubic lice is found in all parts of the world, occurs in all ethnic groups and all levels of society.

Accurate numbers are difficult to acquire, because pubic lice infestations are not considered a reportable condition by many governments.

Many cases are self-treated or treated discreetly by personal physicians, which further adds to the difficulty of producing accurate statistics.

[7] It has been reported that the trend of pubic hair removal has led to the destruction of the natural habitat of the crab louse populations in some parts of the world, thereby reducing the incidence of the disease.