| Pubic lice (crabs, crab lice) | Pubic lice (crabs, crab lice) | The pubic or crab louse is an insect pest of humans spread almost exclusively by intimate or sexual contact. That said, it is possible to become infested from contact with contaminated clothing or bedding, but the most common non-sexual infestations occur when using public toilets. This is less likely, however, as crab lice do not survive long without a human host, usually less than 24 hours. Crab lice feed on human blood. Typically crab lice live and feed in the pubic and perianal region, often causing itching and irritation, sometimes with a blue dotted rash. Small black or rust-colored specks of louse feces in the underwear can also be a sign of infestation.
Crab lice may be found as adult insects, nymphs or immature insects, or eggs (nits). Adult lice are usually found in the pubic area on or near the skin where they feed. Adult lice can crawl quickly, but do not fly or jump. Eggs or nits are found near the base of the hair shafts. Occasionally crab lice have been found on other coarse body hairs, such as armpit hairs, beards, or eyebrows. Adult insects range in color from pinkish-tan to grayish-white. They are about as long as they are wide, typically about 1-2 mm in length (around 1/16”). They are broadly oval and flattened in appearance. Nymphs resemble adults, but may be somewhat smaller. The oval, yellowish to white eggs are the easiest stage to find, as they are not mobile but are cemented tightly to the hair shaft near the base of the hair. The empty egg case will remain attached to the hair after hatching, making it difficult to determine if the infestation has been eliminated. However, nits further than 1/4” from the skin have usually either hatched or are dead. Use a lice comb or pick nits off with your fingernails. Keep in mind that nits are very difficult to remove but need to be removed to stop the infestation. |
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