Pubic lice

Definition

Pubic lice are tiny wingless insects that infect the pubic hair area and lay eggs there. These lice can also be found in armpit hair, eyebrows, mustache, beard, around the anus, and eyelashes (in children).

Alternative Names

Pediculosis - pubic lice; Lice - pubic; Crabs; Pediculosis pubis; Phthirus pubis

Causes

Pubic lice are most commonly spread during sexual activity.

Although not common, pubic lice can spread through contact with objects such as toilet seats, sheets, blankets, or bathing suits (that you may try on at a store).

Animals cannot spread lice to humans.

Other types of lice include:

You are at greater risk for pubic lice if you:

Symptoms

Pubic lice cause itching in the area covered by pubic hair. Itching often gets worse at night. The itching may start soon after getting infected with lice, or it may not start for up to 2 to 4 weeks after contact.

Other symptoms can include:

Exams and Tests

Your health care provider will do an exam to look for:

Because pubic lice may cause an eye infection in young children, eyelashes should be looked at with a high-powered magnifying glass. Sexual transmission, and potential sexual molestation, should always be considered if pubic lice are found in children.

Adult lice are easy to identify with a special magnifying device called a dermatoscope. Pubic lice are often referred to as "the crabs" because of their appearance.

Teenagers and adults with pubic lice may need to be tested for other sexually transmitted infections (STIs).

Treatment

MEDICINES

Pubic lice are often treated with medicines that contain a substance called permethrin. To use this medicine:

In case of eyelash infestation, applying soft paraffin three times daily for 1 to 2 weeks may help.

Most people need only one treatment. If a second treatment is needed, it should be done 4 days to 1 week later.

Over-the-counter medicines to treat lice include Rid, Nix, LiceMD, among others. Malathion lotion is another option.

Sexual partners should be treated at the same time.

OTHER CARE

While you are treating pubic lice:

Outlook (Prognosis)

The proper treatment, including thorough cleaning, should get rid of the lice.

Scratching can make the skin raw or cause a skin infection.

When to Contact a Medical Professional

Call for an appointment with your provider if:

Prevention

Avoid sexual or intimate contact with people who have pubic lice until they have been treated.

Bathe or shower often and keep your bedding clean. Avoid trying on bathing suits while you are shopping. If you must try on swimwear, be sure to wear your underwear. This may prevent you from getting or spreading pubic lice.

References

Burkhart CN, Burkhart CG, Morrell DS. Infestations. In: Bolognia JL, Schaffer JV, Cerroni L, eds. Dermatology. 4th ed. Philadelphia, PA: Elsevier; 2018:chap 84.

Centers for Disease Control and Prevention website. Parasites. www.cdc.gov/parasites/lice/pubic/treatment.html. Updated September 12, 2019. Accessed February 25, 2021.

Katsambas A, Dessinioti C. Parasitic diseases of the skin. In: Kellerman RD, Rakel DP, eds. Conn's Current Therapy 2021. Philadelphia, PA: Elsevier; 2021:1061-1066.

Marcdante KJ, Kliegman RM. Cutaneous infestations. In: Marcdante KJ, Kleigman RM, eds. Nelson Essentials of Pediatrics. 8th ed. Philadelphia, PA: Elsevier; 2019:chap 196.


Review Date: 11/10/2020
Reviewed By: Ramin Fathi, MD, FAAD, Director, Phoenix Surgical Dermatology Group, Phoenix, AZ. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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