Pubic lice are a parasite known as phthirus or pediculosis pubis but is commonly referred to as crabs. These small, wingless ‘insects’ are found mainly on the genital area although they can be present on coarse hair like the eyebrows, beard and eyelash areas. Pubic lice are blood sucking insects that are transmitted either through direct contact or through contact from infested towels, linen or clothing. Due to the consumption of blood, the lice may appear reddish-brown (rust) in color. This condition of pubic lice affects individuals of both genders.

How long do pubic lice/crabs last?

The life cycle of the pubic lice, from the egg to adult stage, occurs in a time span of approximately one month. These parasites are difficult to remove as they are firmly anchored at the base of the hair. Mainly found on the genital area, the pubic lice are small insects that pierce and inject the skin with saliva to prevent clotting so that it can feed on the blood.

There 3 stages of lice development :

1. The egg (nit) – Nits are eggs laid by the adult pubic lice at the base of the hair shaft. Once laid it takes approximately 2 weeks to hatch. The nits appear yellow to white in color and are characterized by its oval shape. They are small in appearance making it difficult to notice.
2. The nymph – The nit hatches into a baby louse called a nymph which matures into adult lice within a period of 7 days of hatching.
3. Adult lice – The adult lice appears in a greyish-white to reddish-brown in color with a live span of 30 days. These lice are dependent on blood for their survival.

Pubic lice will persist for months or years unless appropriate treatment is commenced.

Picture of a Pubic Liouse (Crabs) from the Oklahoma State University

Causes of Pubic Lice

Pubic lice, is a condition caused by the infestation of the parasite known as phthirus. These parasites travel quickly between hosts increasing the risk of transmission through sexual contact if the individual is infected and if many sexual partners are involved. The pubic lice cannot jump between individuals and are unable to survive without a host. Pubic lice therefore cannot infect individuals from toilet seats.

Signs and Symptoms of Crabs

• The presence of black powdery droppings on the underwear is an indication of pubic lice infestation
• Frequent and intense itching caused by an allergic reaction to the saliva of the pubic lice.
• Due to the scratching caused by the itching, the affected area becomes inflamed (red and swollen). The scratching can cause a break in the skin which can lead to a secondary bacterial infection. The area becomes red and tender increasing the spread of the pubic lice.
• A flat bluish-grey rash may occur on the stomach, arms, and legs.
• Visible crawling lice or eggs on the pubic area often indicates an infestation.

Treatment of Pubic Lice Infestation

• Over-the-counter (OTC) medication as advised by a qualified medical doctor is usually effective. Permethrin, pyrethrin and lindane are 3 common medications used in the treatment of this condition.
• Infected linen, towels and clothing should be carefully laundered preferably by machine. Dry launder the washing using a high temperature for at least 20 minutes as the heat would kill off any remaining lice.
• It is advisable to abstain from sex during the time of treatment to prevent a recurrence of the condition.
• Medicated formulations take approximately 3 to 7 days and are effective in the treatment of lice infestation. Saturate the pubic hair with the prescribed medication leaving it on for the allocated time. Rinse off thoroughly with water and dry the pubic area using a clean dry towel. The remaining nits can be removed with the use off the fingernails.