Healthcare provider explaining to patient whether crabs are an STD

Are Crabs An STD?

Written on November 24, 2023 by Amy Harris, MS, RN, CNM. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

Crabs is another name for pubic lice. Somewhere between two and 10 percent of the world’s population has public lice.[1] Are you itching or feeling your skin crawl yet? Lice are never a pleasant conversation topic, no matter where on your body they call home. Keep reading Everlywell’s guide to this easily-treated, common infection.

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What Are Crabs?

People nicknamed public lice crabs because their bodies are shaped like a crab’s body. Crabs are tiny (pin-head sized or 1/16 of an inch or less) parasites that attach to the hairs around your genitals.[2] They are part of a happy family of three different types of lice that infect humans:

  1. Pediculus humanus capitis: head lice
  2. Pediculus humanus corporis: body lice
  3. Phthirus pubis: pubic lice

According to the Centers for Disease Control (CDC), pubic lice have three forms: the egg (also called a nit), the nymph, and the adult. Pubic lice nymphs take about 2–3 weeks after hatching to mature enough to reproduce as adults.[3] Crabs feed on your blood to survive. They will die without their human home (and food).[4] If they fall off of you, they usually die within 1-2 days. Nymphs and crabs need to feed up to five times a day.

What Are The Symptoms of Crabs?

Itching is the primary symptom people with crabs report. When crabs bite your skin, their saliva causes intense itching.[2] Other signs you might have crabs are [4]:

  1. Finding little white dots (eggs or nits) at the base of the hair follicles around your genitals.
  2. Seeing slow crawling immature crabs (nymphs) around your genitals or public hair.
  3. Small blood spots in your underwear or black spots, which are crab droppings.

Sometimes, it can be hard to see crabs — typically, only a few crabs hang out together at a time.[4] Using a magnifying glass to look may help you sleuth out whether or not you have crabs.

If You Have Genital Itching, Do You Have Crabs?

Not necessarily. Several other STDs cause itching, such as [5]:

Also, remember that getting pubic lice doesn’t mean you’re dirty — your infection has nothing to do with your hygiene or cleanliness, just your sexual activity.[6]

Is There a Test or Treatment for Crabs?

There is no test for crabs. If you see crabs, nits, or nymphs on your skin, you could see a healthcare provider for confirmation that you have crabs. They could then prescribe you (and any sexual partners) a treatment for crabs.

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If you have itching and have seen crabs on your body, you can try an over-the-counter cream or lotion treatment. Nix™ lice treatment products are one example. These treatments kill the parasites and their eggs. Treatments include a lotion that contains permethrin or a mousse containing pyrethrins and piperonyl butoxide.[4] One treatment (assuming you follow the package instructions) usually will cure your crab problem. Some people may require a second treatment 9-10 days later. Here is how to use an over-the-counter crab treatment:

  1. Before you apply any treatment, wash the infected area (your pubic region) with soap and warm water.
  2. Dry the area with a clean towel and wash and dry this towel in a washing machine and high-heat dryer to avoid contaminating other clothing or bedding.
  3. Do not shave your genital area before applying crab treatment.
  4. Follow the package instructions carefully. In general, leave shampoos on for about 10 minutes and lotions and creams for 8-14 hours.
  5. When your time is up, rinse off your crab treatment with warm water. Rinsing away the product will also help to remove dead nits and lice from your skin.

If you find nits at the base of the hair, you can just remove them using your fingernails or a fine-toothed comb. Make sure your crabs are gone for good by:

  • Sterilizing any comb used by washing it with hot, soapy water.
  • Using clean tweezers to pluck away the nits carefully. This will prevent them from hatching, causing another outbreak of pubic lice a few weeks later.
  • Shaving to get rid of any remaining nits after completing all nit-removing steps.
  • Throwing the clothes you wore before your treatment in the washing machine. Use hot 140°F (60°C) water to kill any nits or lice.

You should see a healthcare provider if you have any questions about whether or not you have crabs or another STD if over-the-counter products don't kill the lice after the first treatment, if you're pregnant, or if you have any infected skin areas from scratching.[2]

To prevent the spread of crabs to family members or other partners, avoid having sexual contact or sharing bedding or clothing with anyone until you are fully treated. If you are treated for pubic lice, all of your sexual partners also need treatment — otherwise, you will just keep reinfecting one another.[6]

Are Crabs An STD?

A sexually transmitted disease (STD) is a condition caused by an infection with a virus, bacteria, or parasite that spreads from one person to another through some kind of sexual activity.[5]

Crabs spread by crawling — they can’t fly or jump. You can’t get crabs from animals.[4] They spread most commonly through sexual activity, so yes, they are an STD.[1] But you can still get crabs without having sex. Any close genital-to-genital contact could help crabs hitch a ride on a new human host — passing on crabs to your partner does not require having penetrative oral or anal sex like some other STIs.

It may be possible to catch pubic lice after sharing clothing, bedsheets, or towels with an infected person as well.[2] It is hard for pubic lice to survive on smooth surfaces, like toilet seats, because they usually slip off. Pubic lice can spread to other parts of your body with coarse body hair, including your [1-2]:

  • Armpits
  • Legs
  • Eyelashes or eyebrows, more commonly in children
  • Chest
  • Beard or mustache

Cases of crabs in the eyelashes and eyebrows may be a red flag for potential child sexual abuse.[15]

Research shows that many of the same people who have crabs may have other sexually transmitted infections.[2,6] If you or one of your partners is dealing with crabs, it might be a great time to test for other STDs as well. Everlywell offers convenient and confidential at-home STI testing for 6 common STDs: Gonorrhea, chlamydia, HPV, Hepatitis C, Syphilis, and Trichomoniasis.

How Can Everlywell Can Help Improve Your Sexual Health and Wellness?

Worrying that you might have an STD is no walk in the park. Not sure what your symptoms mean or which test is right for you? Everlywell offers access to online STD consults with highly-trained clinicians within two hours. Clinicians are available in select states Monday-Friday, 7 a.m.-6 p.m. CST. Your sexual health is an essential part of your overall health and well-being.

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Does Showering After Sex Reduce Chances of STDs?

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What Causes Pain During Sex In Females?

References

  1. Anderson AL, Chaney E. Pubic lice (Pthirus pubis): history, biology and treatment vs. knowledge and beliefs of US college students. Int J Environ Res Public Health. 2009;6(2):592-600. doi:10.3390/ijerph6020592.
  2. Pubic lice (crabs). Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/pubic-lice-crabs/symptoms-causes/syc-20350300. Accessed November 14, 2023.
  3. Parasites: Pubic lice (Crabs) FAQs. CDC. https://www.cdc.gov/parasites/lice/pubic/gen_info/faqs.html. Published September 17, 2020. Accessed November 14, 2023.
  4. Pubic lice, Crabs. MedlinePlus. https://medlineplus.gov/pubiclice.html. Published November 30, 2023. Accessed November 13, 2023.
  5. Common STD symptoms. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/sexually-transmitted-diseases-stds/in-depth/std-symptoms/art-20047081. Published May 5, 2022. Accessed November 13, 2023.
  6. Public lice (crabs). Planned Parenthood. https://www.plannedparenthood.org/learn/stds-hiv-safer-sex/pubic-lice. Published. Accessed November 14, 2023.
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