Crab Lice



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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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

Factors that raise your risk are:

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



You may have:

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


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.



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.


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

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.

a (Pubic Lice; Pediculosis Pubis)


American Academy of Dermatology 

The American Congress of Obstetrics and Gynecology 


HealthLink BC 

Health Canada 


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: Updated July 16, 2015. Accessed August 1, 2018.

Medication guide lindane shampoo. Food and Drug Administration website. Available at: Accessed August 1, 2018.

Parasites—lice. Centers for Disease Control and Prevention website. Available at: Updated September 24, 2013. Accessed August 1, 2018.

Pediculosis pubis. EBSCO DynaMed Plus website.  . Updated June 9, 2015. Accessed August 1, 2018.