Crab Lice

(Pubic Lice; Pediculosis Pubis)

Definition

Crabs, or pubic lice, are tiny blood sucking parasites. They are usually found in the pubic hair. They can also be found in other body areas with short hair, such as the eyelashes, eyebrows, armpit hair, and mustache hair.

Pubic lice are often called crabs because they look like tiny crabs.

Pubic Louse

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Causes    TOP

Crab lice are parasites. They are insects that need to live off of a host. Crab lice are spread by contact with a person, usually during sex. Less often, crab lice may also spread by sharing items like bedding, towels, and clothing.

Risk Factors    TOP

Factors that raise your risk are:

  • Sex with someone who has crab lice
  • Contact with contaminated items, such as:
    • Bedding
    • Towels
    • Clothing

Symptoms    TOP

You may have:

  • Intense itching
  • Lice or eggs on your hair
  • Tiny blue bumps on your skin

Diagnosis    TOP

You will be asked about your symptoms and health history. A physical exam will be done. Your doctor will be able to diagnose crab lice by viewing lice and lice eggs.

Treatment    TOP

Pubic lice can be treated with an over the counter shampoo or cream rinse.

If the lice do not go away, you may be given topical medicine or pills. Some of these medicines have risks. Tell your doctor if you are pregnant, breastfeeding, or have health problems.

Prevention    TOP

Avoid close physical or sexual contact with anyone who has crab lice.

RESOURCES:

American Academy of Dermatology
https://www.aad.org
The American Congress of Obstetrics and Gynecology
http://www.acog.org

CANADIAN RESOURCES

References:

Centers for Disease Control and Prevention. Sexually Transmitted Diseases Treatment Guidelines, 2010. MMWR 2010;59(No. RR-12):1-110.
Lindane shampoo and lindane lotion. Food and Drug Administration website. Available at:
...(Click grey area to select URL)
Updated July 16, 2015. Accessed August 1, 2018.
Medication guide lindane shampoo. Food and Drug Administration website. Available at:
...(Click grey area to select URL)
Accessed August 1, 2018.
Parasites—lice. Centers for Disease Control and Prevention website. Available at:
...(Click grey area to select URL)
Updated September 24, 2013. Accessed August 1, 2018.
Pediculosis pubis. EBSCO DynaMed Plus website. http://www.dynamed.com/topics/dmp~AN~T114055. Updated June 9, 2015. Accessed August 1, 2018.
Last reviewed June 2018 by EBSCO Medical Review Board Beverly Siegal, MD, FACOG
Last Updated: 8/1/2018

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