Pubic Lice (Crabs)

By Matthew Cenzon. May 7th 2016

Commonly referred to as "crabs," pubic lice are a bodily nuisance that can lead to severe itching and an embarrassing visit to the doctor's office. They spread through close contact with an infected individual, primarily during sexual intercourse. Fortunately, they can be easily treated with over-the-counter or prescription medication. Use this article to help you determine whether you are afflicted by a pubic lice infestation.

What Are Pubic Lice?

Much like their head lice counterparts, pubic lice are small, six-legged pests that are typically found around the pubic region, although they can also be found around the eyebrows or armpits. They have been referred to as "crabs" due to their crab-like appearance. These wingless insects are parasitic in nature, feeding specifically off of the blood from their host's body. They are usually found attached to a person's pubic hairs, and range from 1.1 to 1.8 millimeters in length.

Causes and Risk Factors

Pubic lice infestation is a condition that is typically spread through sexual activity, but can also be spread from person-to-person through objects that come into contact with affected regions of the body like toilet seats, underwear, sheets and bathing suits. Crabs, or any other type of human lice for that matter, cannot be spread from animals to humans. Risk factors include:

  • Having multiple sex partners
  • Sexual acts with a person infected by crabs
  • Sharing bedding or clothing with an infected person
  • Coming into contact with an object that has a high likelihood for harboring crabs, like a toilet seat

One thing to consider is trying on undergarments or bathing suits at a store or shopping mall. These articles of clothing can be tried on by numerous people with a high probability that they are not cleaned or washed when returned to the clothing rack. Most stores that sell these types of garment warn customers to try on undergarments and bathing suits over their clothing to prevent the spread of germs and pubic lice.


The main symptom for pubic lice infestation is severe itching in the most commonly affected regions of the body, primarily the pubic region. Bite marks from pubic lice can leave marks around the affected areas. Pubic lice and their eggs can appear like small debris or crust around the hairs of the pubic region. When imbedded around the eyebrows, they may appear on the edges of a person's eyelids and eyelashes. Other symptoms include:

  • The skin around the affected area may turn bluish-gray in appearance
  • Bite marks that take on the appearance of small bruises
  • Irritated skin due to excessive scratching
  • Scratching may also lead to further infection


A physician can visually inspect the affected area and search for any signs of crabs. This includes looking for pubic lice and their eggs around the hair. A fine-toothed comb can also help with the visual inspection, similar to head lice. Bite marks on the body and any traces of crabs on a person's clothing are other signs the physician will take note of.


Crabs will not go away on their own and must be treated immediately to avoid infection from excessive scratching. Treatment for crabs can be performed with over-the-counter (OTC) medication. Medication includes creams, lotions or shampoos that will assist with eradicating the affected area of any pubic lice and their eggs. If symptoms persist after an OTC treatment is administered, medical attention should be sought for prescription medication.

A single treatment of OTC or prescription medication is all that is typically needed to treat pubic lice. However, if symptoms do not subside, it is recommended that the individual administer a second treatment 4 days to 1 week after the first treatment.

The best form of treatment for pubic lice is with a medicated shampoo containing permethrin. The shampoo should be lathered and scrubbed thoroughly into the affected hair for a minimum of 5 minutes. Upon rinsing off, a fine-tooth comb should be used to remove any eggs that may still be attached to the hair.

All clothing and bedding should be washed in hot water to ensure the individual will not have a repeat infestation. Items that cannot be washed should be sprayed with disinfectant and stored in sealed plastic bags for 10 to 14 days.


Personal hygiene is one of the key factors in preventing crab infestation. Never try on bathing suits or undergarments completely naked. If these articles of clothing must be borrowed, try to wash them before use in hot water. Avoid having sexual contact with individuals who are possibly infected, and always practice safe sex. Individuals who became infected by crabs should inform their sexual partners so that they too can be treated to help prevent the spread of pubic lice.


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