ABSTRACT
ETIOLOGY AND EPIDEMIOLOGY Crab lice (12.1) are approximately 1 mm in length with a wider, shorter body than head lice and they resemble tiny crabs. Their eggs, which are attached to human hairs, are viable for up to 10 days; the adult crab lice can live for at least 36 hours away from the host. Crab lice have serrated edges on their first claw that enable them to ambulate on the entire body surface1. The incidence is slightly higher in men, most likely due to the increased amount of coarse body hair. Infestations with crab lice can be found in all levels of society and all ethnic groups, although those of Asian descent or with minimal pubic hair are rarely infested. Infestation is most frequently observed in those 15-40 years of age, correlating with increased levels of promiscuous sexual activity. Although infestation is often considered a sexually transmitted disease, individuals who have had no sexual exposures are occasionally infested via fomite transmission2.
