Fact #4: The average adult pubic louse is between 1.3 and 2 mm long.

The Crabs STD

What Are Crabs 

The Crabs STD Under A Microscope

The STD crabs, also known as pubic lice, are tiny insects that infest the pubic hair region and lays their eggs in this area. These pests can also be found in the eyebrows, armpit hair, and the hair surrounding the anus. They are characterized by dark dots (the lice) in the genital region, bluish-grey skin, itching of the region infested with crabs, and/or sores in the region with the crabs caused by biting. Crabs is a sexually transmitted disease, so it is primarily transmitted through sexual acts, but it can also rarely be transmitted through fabrics (underwear and sheets) and hard surfaces (toilet seats).

For more on what crabs are, check out this question answered on the What Are Crabs? common questions page.

What Causes Crabs 

Your chance of getting crabs is increased if you:

  • Live in close proximity with somebody who is infected with crabs.
  • Have several sexual partners.
  • Have a sexual partner who has many sexual partners.
  • Share bedding or clothing with an infected person.

Crabs, as their status as an STD would suggest, are passed from person to person through sexual activities. They are most common in younger populations, predominantly teenagers, like most STD's, because of increased promiscuity in younger populations.

If someone has pubic lice, it doesn't necessarily mean that they are sexual active with someone else that has it. Although rare, crabs can be transmitted through objects such as underwear, shirts, sheets, blankets, clothes in a store, and toilet seats.

Crabs can not be passed between animals and people anymore than it can be spread between people and objects, so it would be very unlikely to be passed between the two.

Crabs/pubic lice are very similar to head and body lice, sharing many of the same symptoms and treatments.

Crabs Symptoms (more) 

The Crabs STD Symptoms Being Shown

Crabs live off human blood and leave behind a protein when feeding making the skin itchy and red. This itching often gets progressively worse during the nighttime. People who become infected can show symptoms immediately after being infected or they can go for a few weeks without showing any signs of having them. Within a month after getting the public lice, though, symptoms should be visible.

Some obvious symptoms include:

  • Small dark grey, dirt-like bugs in the pubic, armpit, eyebrow, or anus regions.
  • Bluish-grey skin around the infected area.
  • Sores in the area with crabs due to the biting.

For more information about the symptoms of crabs, read our crabs symptoms page.

Testing for Crabs 

Tests for crabs are most often non-intrusive, but if you are being tested for crabs it is not uncommon that you will be tested for other STD's. The tests performed by your healthcare professional includes looking for:

  • Small light-grey ovals or nits (eggs and larvae) attached to the pubic hair in the outer genital region.
  • Adult crabs in the genital or other regions.
  • Signs of an infection or scratch marks in the infected area.

In children, pubic lice can cause an infection in the eye, so the eyelashes are often looked at under a microscope.

Adult pubic lice are generally easily identifiable because of their crab-like appearance, especially under a microscope.

Treatment for Crabs (more) 

It is often suggested that a perscription is given to ensure that the crabs have been completely eliminated, but the over-the-counter products used for head lice is just as effective at pubic lice and usually gets rid of all of them.

If a shampoo is being used it should be thoroughly applied to all of the hair and left on for 5 minutes, or the amount of time recommended by the product's packaging. After this time has been given it should be completely and thoroughly washed out. After it has been washed out you should comb your hair to make sure the eggs (nits) of the crabs are out as well. Generally the product is used for only one or two treatments.

If you use Malathion lotion the directions on the product's container should be followed. Generally the lotion needs to be applied to the dry scalp until wet, then left on for 8 to 12 hours then rinsed out.

Once you have gotten rid of all of the crabs, all of your bedding, clothing and surfaces you regularly come into contact with should be washed extremely well to make sure there are no crabs left behind.

For more information about crabs treatment, read our treatment page.

Preventing Crabs (more) 

Crabs (STD), is very preventable, but the methods are very different than that of other STD's. Of course it is always a good idea to practice safe sex outside of a monogamous relationship, but no form of birth control is effective in stopping the spreading of crabs. Since crabs live in pubic hair, one simple solution to prevent the spread of the STD crabs would be to get rid of all of your pubic hair. But if this is not an option you would like to entertain, the best form of prevention would probably be to ensure that your sexual partners are not infected with crabs themselves. This can be done simply by asking them, or by inspecting their pubic hair region for any of the symptoms we have listed. Even if you do get pubic lice, they are very easy and affordable to treat, with treatments available over-the-counter.

For more information about crabs prevention, read our crabs prevention page.

Informative Video 

More Resources 

For more general information about crabs, please check out Wikipedia's crab louse page. For further reliable crabs treatment and other STD information, please see Planned Parenthood.

For STD awareness and information, please visit FrontLineKC. Here you will find up-to-date news, articles, and information about various sexually transmitted diseases.