What Are Itching Crabs?

"Itching crabs" is a slang term for Pthirus pubis, variously known as pubic lice, crab lice or simply crabs. A type of parasite, crabs receive the name from the resemblance to tiny crabs, complete with miniature claws with which they grasp the host victim's hair. Crabs live only on humans, preferring the pubic hair but are occasionally found in beards, eyebrows, armpits or anywhere coarse hair is present. Crabs, as the term "itching crabs" suggests,l make you itch -- a lot.

Pubic Crabs

• Crabs are one of three types of lice that infest humans: body lice, head lice and pubic lice. Named for the body area inhabited, pubic lice can occasionally be found in head hair. About the size of a sesame seed, crabs are visible to the naked eye as small brown to gray specks; they can even be mistaken for a freckle or mole until they begin moving. Crabs have a single-minded purpose in life: to drink your blood and to reproduce.

Feeding Habits

• Crabs grow from egg stage -- called a nit -- to adulthood, totally dependent on the human host upon which it feeds; both larvae and adults will die within about a day if they fall off the host because they need the heat and humidity which the host provides. In adulthood, crabs begin feasting in earnest, making a meal of the host's blood every four-to-eight hours. Crabs, like all lice family members, are host-specific and cannot transfer from humans to other animals.

Reproduction

• Female crabs need blood meals to develop the eggs, which they subsequently glue onto the hairs of the human host. About the size of a pin-needle head, the nits prove more difficult to spot and even harder to remove. Adult crabs live approximately a month and during this time the female might lay 20-to-30 eggs each. New nits rapidly hatch, growing through nymph stage -- childhood -- and to adulthood, when the life cycle begins again.

Symptoms

• By the time you begin itching, your exposure to the crabs occurred two or three weeks previous. Intense itching, called pruritus, caused by your body's allergic response, is the most common symptom and often proves worst at night. Bluish-gray marks, red spots, lumps and signs of irritation also result from the crab's bite. Close inspection will reveal tiny crabs and nits in the effected area.

Treatment and Prevention

• Many health professionals consider crabs a sexually transmitted disease, since they usually spread through intimate contact. They may even transfer from the genital region to beards and eyebrows during oral sex. However, non-sexual contact can transmit crabs through infested towels, clothing or sheets and even toilet seats -- although uncommon. The Centers for Disease Control and Preventions suggests using permethrin creams, available in over-the-counter products, or prescription medicines to treat crabs. Shaving also helps eliminate crabs but is not strictly necessary. Wash sheets, clothing and other contaminated items for treatment to prove successful. Treat sexual partners to prevent re-infestation, and consult a doctor if infection results.