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, armpits, and mustache.
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 for crab lice include:
The doctor will ask about your symptoms and medical history. A physical exam will be performed. 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 treatment above. For resistant cases, your doctor may recommend:
Recommended treatment steps:
To reduce the chance of getting crabs or spreading crabs:
American Academy of Dermatology
American College of Obstetrics and Gynecology
Communicable Disease Control (CDC) Network
Province of Manitoba
Behrman RE, Jensen HB, Nelson WE, Kleigman RM. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, PA: Saunders Elsevier; 2007.
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. US Food and Drug Administration website. Available at: http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm110452.htm. Updated June 2009. Accessed July 9, 2009.
Medication guide lindane lotion. US Food and Drug Administration website. Available at: http://www.fda.gov/cder/drug/infopage/lindane/lindaneLotionGuide.htm. Updated August 2007. Accessed July 9, 2009.
Medication guide lindane shampoo. US Food and Drug Administration website. Available at: http://www.accessdata.fda.gov/drugsatfda_docs/label/2003/006309shampoolbl.pdf. Updated August 2007. Accessed July 9, 2009.
Pickering LK, American Academy of Pediatrics Committee on Infectious Diseases, et al. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2006.
Pubic "crab" lice fact sheet. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/lice/pubic/factsheet.html. Updated May 2008. Accessed July 9, 2009.
Rapini RP. Parasitic infestations. American Academy of Dermatology website. Available at: http://www.aad.org/education/students/parainfest.htm. Accessed July 9, 2009.
Revised lindane lotion label. US Food and Drug Administration website. Available at: http://www.fda.gov/cder/foi/label/2003/006309lotionlbl.pdf. Accessed July 9, 2009.
Revised lindane shampoo label. US Food and Drug Administration website. Available at: http://www.accessdata.fda.gov/drugsatfda_docs/label/2003/006309shampoolbl.pdf. Accessed July 9, 2009.
Last reviewed October 2012 by Brian Randall, 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.