[6] The eggs of the crab louse are laid usually on the coarse hairs of the genital and perianal regions of the human body.

In some infestations, a characteristic grey-blue or slate coloration appears (maculae caeruleae) at the feeding site, which may last for several days.

[9] Crab louse infestations are not considered a reportable condition by many health authorities, and many cases are self-treated or treated discreetly by physicians.

[10] It has been suggested that an increasing percentage of humans removing their pubic hair, especially in women, has led to reduced crab louse populations in some parts of the world.

Crab louse infestation is found worldwide and occurs in all races and ethnic groups and in all socio-economic levels.

[17] Symptoms of crab louse infestation in the pubic area include itching, redness and inflammation.

Crab lice are not known to transmit disease;[citation needed] however, secondary bacterial infection can occur from scratching of the skin.