The human pubic louse, Pthirus pubis, is a parasitic insect that feeds only on the blood of humans. More commonly known as "crabs", pubic lice infest approximately 1 in 90 Americans every year. They cause irritating, while relatively harmless, symptoms but can leave skin susceptible to more dangerous secondary infections.
What Are They?
Pubic lice are insects and as such have six legs. They have a squat, heart-shaped body with six burly legs which protrude from the sides. Four of their legs are particularly bulky with large claws on the ends.
Pubic lice have received the nickname "crabs" due to their resemblance of the crab-shaped body and arms. They live in areas where relatively sparse, coarse hair grows, such as that of the groin, anus, abdomen, and face (eyelashes, eyebrows, beards and mustaches). Their life cycle is composed of nits (eggs), nymphs (immature lice), and adults (sexually mature lice), all of which require human contact to survive.
How Can You Get Them?
Most pubic lice are transferred during sexual contact. Having multiple sex partners increases the risk for contracting pubic lice. However, they can also be transferred by sharing towels, clothing, or bed linens. Most child cases of pubic lice are seen on the eyebrows and are the result of sharing a bed with an infected parent. You cannot get pubic lice from toilet seats or the carpets and furniture of an infected individual. Pubic lice cannot grab onto the smooth surface of a toilet seat. And while they may be able to grab the fibers of carpet or furniture, they will be unlikely to grab another host unless that furniture or carpet is frequented by a scantily clothed person. Most lice cannot survive longer than 2 days without a human host.
What Happens When You Get Crabs?
When a nymph or adult louse transfers from one host to another, they will seek out the coarse hair they desire. They will take several blood meals a day by biting the skin surrounding the base of hair follicles. The adult female lice, after only 2 days of gestation, will lay eggs and attach them to the base of hair follicles with a cement-like substance, greatly inhibiting their easy removal. The bite marks from feeding will most likely become inflamed, resulting in blue-gray spots and eventually raised itchy, red papules. Symptoms usually occur within 5 days of initial infestation. Adult lice will look like small bits of dead skin to the naked eye but can be seen fairly well with a magnifying glass. Eggs will look like very tiny white or gray dots in the pubic hair.
How Do You Treat Crabs?
All stages of pubic lice can be treated with medicated creams or shampoos without the need of shaving hair. There do exist all natural remedies for pubic lice. To prevent re-infection all bed linens, clothing, and bath towels should be washed in hot water and thoroughly dried in a hot drier.