Adult pubic lice (or crab lice) are 1.1-1.8 mm in length. They are commonly found attached to hair in the pubic and genital area. Sometimes, pubic lice and eggs are also found on other coarse body hairs like eyebrows, eyelashes, beard, mustache, and those on the chest and armpits.
Pubic lice infestations (pthiriasis) are usually spread through sexual contact.
Due to strong association of pubic lice infestation and sexually transmitted infections (STI’s), patients with pubic lice infestation and their sex partners should be checked and treated for other STI’s.
Infestation in adults is more common than in children. Parent-to-child infestations are more likely to occur through routes of shared towels, clothing, beds or closets.
Pubic lice can survive only a short time being away from the warmth and humidity of the human body.
Pets do not play a role in the transmission of human lice.
Signs and symptoms
The main symptom is itching, usually in the pubic-genital hair area, because of skin hypersensitivity to biting louse saliva. The itching lasts 2-3 weeks plus bitten sites may become grey-blue or slate coloration for days.
If lice are detected in one family member, the entire family needs to be checked and only those who are infested with living lice should be treated.
There are several medications, over-the-counter and prescribed, for the pubic lice treatment. Following strictly the instructions in the package or on the product label is very important. These products cannot completely remove all nits/eggs cemented to hair shafts. However, these nits can be removed by using fine-toothed comb, forceps or finger nails. Shaving hair in heavily infested area is another option.
Dry clean or machine wash with hot water (at least 130F for 3-5 minutes) can kill lice and nits hiding on cloth, towels, or bedding items that the patient used during 2-3 days before the treatment.
Non-washable items can be treated by storing them in a sealed plastic bag for 2 weeks.
Infested persons and partners must be successfully treated while sexual contacts should be avoided until infestation is ruled out.
Information on Pubic Lice /CDC
Pediculosis / US Nat. Library of Medicine
Crab Louse /University of Florida