Crabs, or pubic lice, are tiny, barely visible parasites. They are usually found in the pubic hair, but can also be found in other body areas with short hair. This may include eyelashes, eyebrows, armpit hair, and mustache hair.
Pubic lice are commonly called crabs because they look like tiny crabs.
Crab lice are parasites. Parasites are insects that need to live off of another animal. Crab lice are spread by personal contact, usually during sexual activity. Less often, crab lice may also spread by sharing personal items. This can include sharing bedding, towels, and clothing.
Factors that increase your risk of crab lice include:
You will be asked about your symptoms and medical history. A physical exam will be done. Your doctor will be able to diagnose crab lice by the appearance of lice and lice eggs in your pubic area.
Your doctor may also check you for other sexually transmitted infections.
Over-the-counter shampoo or cream rinse containing permethrin or pyrethrins are used to treat pubic lice.
Some lice may be resistant to this treatment. For resistant cases, your doctor may advise:
To reduce the chance of getting crabs or spreading crabs:
American Academy of Dermatology
The American Congress of Obstetrics and Gynecology
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: http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm110452.htm. Accessed May 28, 2015.
Medication guide lindane shampoo. Food and Drug Administration website. Available at: http://www.accessdata.fda.gov/drugsatfda_docs/label/2003/006309shampoolbl.pdf. Accessed May 28, 2015.
Parasites—lice. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/parasites/lice. Updated September 24, 2013. Accessed May 28, 2015.
Last reviewed May 2016 by David Horn, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.