Crabs
(Pubic Lice)

Sexually Transmitted Diseases (STDs) Slideshow Pictures A Visual Guide to Erectile Dysfunction Take the Quiz on STDs 5286127

Medical Author:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

View Full Profile

Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

View Full Profile

• Crabs Overview
• Crabs Causes
• Crabs Symptoms
• When to Seek Medical Care
• Exams and Tests
• Crabs Treatment
• Self-Care at Home
• Medication
• Next Steps
• Follow-up
• Prevention
• Outlook
• Synonyms and Keywords
• Authors and Editors

Crabs Overview

"Crabs" is the common term for lice found in the pubic hair of humans. Crabs is a parasite infection medically known as Pediculosis pubis or pubic lice. Barely the size of a pinhead, lice are organisms that live only with the help of another organism, called a host. There are thousands of types of lice, some of which have developed an attraction to humans. The official name for the organism responsible for pubic lice is Pthirus pubis. Other lice that often infect humans are Pediculus humanus capitis (head lice) and Pediculus humanus corporis (body lice). The term "crabs" seems to come from the microscopic appearance of the pubic louse. The pubic lice organisms are visible to the naked eye in affected areas. The lice are typically seen attached to hair in pubic areas, but may sometimes appear in other areas of the body where coarse hair is present (such as beard, chest, armpits, etc.).

The pubic louse is distinct morphologically (somewhat rounded with three pairs of legs on either side of the body from which it takes its descriptive name) from the head and body louse. The female lifespan is slightly shorter (three weeks), and she produces fewer eggs per day (three) than her counterparts. The eggs attach to the base of the pubic hair shaft for approximately six to eight days before hatching.

Picture of pubic louse (crab)

Crabs Causes

• The source of infection for pubic lice is intimate contact with an infected person. Therefore, pubic lice are often transmitted during sex.
  
  
• Since transmission occurs during intimate contact, actual sexual intercourse is not necessary for the spread of pubic lice.
  
  
• Pubic lice can also be transmitted by contact with contaminated belongings such as towels, bed sheets, or clothing.
  
  
• Crabs are transmitted through any intimate contact. Lice do not jump or fly, so actual contact is necessary for transmission. An individual may acquire an infection by sharing bedding or towels.
  
  
• Cats, dogs, and other pets are not involved in the spread of human lice. Your pet cannot become infested with human lice and transmit the lice to another person.