Pubic Lice
The pubic louse (also called a crab louse) has a distinct morphology from head and body louse. It is somewhat round with three pairs of legs on each side of the body (from which it takes its descriptive name). A female louse’s lifespan is slightly shorter (i.e., three weeks), and she produces fewer eggs per day (three or four) than her counterparts. These eggs attach to the shaft of the pubic hair for approximately seven to eight days before hatching.
In adults, the transmission of pubic lice is by direct sexual contact; children may get the pubic lice via nonsexual transmission from their parents. (Sexual transmission may occur in cases of sexual abuse.) Spread of pubic lice by infested clothing and bed linens is less likely and doubted by some.
Intense itching around the pubic area is characteristic. However, eyelashes, axillary regions, and even the scalp may be infested. Symptoms may become worse at night. After a louse bite, a bluish-colored sore may appear in the infected areas. The diagnosis is made by demonstrating crab-shaped lice attached to the pubic hair shaft. Contrary to the popular myth, pubic lice do not spread by toilet seats.