Crabs
(Pubic Lice)
- 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.
Next: Crabs Symptoms »
| Printer-Friendly Format | | | Email to a Friend |
Sex & Relationships
Get tips to boost your love life.
From WebMD
Healthy Resources
Featured Centers
- 12 Ways to Prevent the Spread of Viruses
- 10 Surprising Benefits of Treating Depression
- Healthy Home: To Buy or Not to Buy Organic?
Health Solutions From Our Sponsors
Crabs (Pubic Lice)
Sexually Transmitted Diseases »
Sexually Transmitted Diseases Overview
Sexually transmitted diseases (STDs) are among the most
common infectious diseases in the United States today. More than 20 different
STDs have been identified, and 13 million men and women are infected each year
in the United States. Depending on the disease, the infection can
be spread through any type of sexual activity involving the sex organs
or the mouth; the infection can also be spread through contact with blood during sexual activity.
- STDs affect men and women of all ages and backgrounds.
- STDs have become more common, partly because young people are becoming sexually active at a younger age and are having multiple partners.
- People can pass STDs to sexual partners even if they themselves do not have any symptoms.
- Frequently, STDs cause no symptoms, especially in women.
- Health problems from S...
Read What Your Physician is Reading on eMedicine
Pediculosis »
Pediculosis (ie, louse infestation) dates back to prehistory. The oldest known fossils of louse eggs (ie, nits) are approximately 10,000 years old.
Featured Topics
Explore 80+ Centers
- Allergy
- Allergy Medications
- Anaphylaxis
- Antidepressants
- Anxiety
- Arthritis
- Asthma
- Baby's Health
- Back, Neck, Head Injury
- Bioterrorism, Warfare
- Blood, Lymphatic System
- Bone, Joint, Muscle
- Brain, Nervous System
- Breathing Difficulties
- Burns
- Camping
- Cancer, Tumors
- Children's Health
- Cholesterol
- Cold and Flu
- CPR, Choking
- Cuts, Scrapes, Bruises
- Dementia
- Depression
- Diabetes
- Diabetic Coma, Insulin Shock
- Digestive System
- Dislocations
- Drowning
- Drug Overdose
- Ear, Nose, Throat
- Emotional Wellness
- Endocrine System
- Environmental Injuries
- Erectile Dysfunction
- Exercise, Nutrition
- Eye, Vision
- Fainting
- Fever
- First Aid, Emergency
- First Aid Kits
- Food Poisoning
- Foreign Bodies
- Fractures, Broken Bones
- Glaucoma
- Headache
- Health, Medical
- Heartburn, GERD, Reflux
- Heart, Blood Vessels
- Heart Attack
- Hepatitis
- Immune System
- Incontinence
- Infections
- Kidneys, Urinary System
- Lung, Airway
- Medications
- Men's Health
- Mental Health, Behavior
- Multiple Sclerosis
- Nosebleeds
- Osteoporosis
- Outdoor Living
- Overexposure
- Poisoning
- Procedures
- Psoriasis
- Public Health
- Scuba Diving, Swimming
- Seizures
- Senior Health
- Shock
- Skin, Hair, Nails
- Sleep Disorders
- Social, Family Health
- Sports Injury
- Sprains, Strains
- Statins
- STDs
- Substance Abuse
- Teen Health
- Teeth, Mouth, Oral Health
- Weight Management
- Wilderness Emergencies
- Women's Health
- Wounds

