Pubic Lice (Crabs) Guide: Symptoms, Causes, Diagnosis, and Treatment
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
TL;DR
Pubic lice — commonly called crabs — are tiny insects about 1/16 inch (1.6 millimeters) or smaller that live in the genital hair and feed on blood, causing intense itching. They spread most often through close sexual contact, moving from one person's hair to another, and less often through shared bedding, towels, or clothing. They can also move to the legs, chest, armpits, beard, and eyelashes or eyebrows (especially in children). Treatment usually starts with an over-the-counter lotion or shampoo containing permethrin or pyrethrin, followed by hot-water laundry at at least 130°F (54°C), and — critically — treatment of all sexual partners, which is what breaks the cycle for good.
Quick Answer
What are pubic lice? Tiny crab-shaped insects, 1/16 inch or smaller, that live in genital hair and feed on blood. They are different from head lice and body lice.
How do you get them? Most often through close sexual contact; less often by sharing bedding, towels, or clothing with someone who has them.
What are the symptoms? Intense itching in the genital area; lice can spread to the legs, chest, armpits, beard, and eyelashes or eyebrows (more often in children).
How is it diagnosed? A visual check of the genital area — seeing moving lice confirms the diagnosis; nits alone can cling to hair even after successful treatment.
How is it treated? Over-the-counter permethrin or pyrethrin lotion or shampoo applied as directed, hot-water washing of bedding and clothing, and treatment of all sexual partners. Prescription options exist if over-the-counter treatment fails.
What Are Pubic Lice?
Pubic lice are small insects that live in the genital hair. They are sometimes called crabs because their body shape resembles a tiny crab.
They are notably small — measuring 1/16 inch (1.6 millimeters) or less — and they are not the same insects as head lice or body lice. Pubic lice are their own species with their own habits.
Pubic lice are different from head lice and body lice. They measure 1/16 inch (1.6 mm) or less, feed on blood, and are nicknamed crabs because of their crab-like body shape.
Pubic lice feed on human blood, and it is their bites that cause the serious itching most people notice first. The good news is that treatment is straightforward: lotions and shampoos that kill both the lice and their eggs are available without a prescription.
What Are the Symptoms?
The hallmark symptom of pubic lice is a bad itch in the genital area. The itching comes from the lice bites and tends to be persistent and intense.
Lice can also move beyond the genital area to other parts of the body with thick hair. The table below shows where they can spread.
Body area | Notes |
|---|---|
Legs | Thickly haired leg areas can become involved |
Chest | Hairy chests are a common secondary site |
Armpits | Lice can spread to the armpit hair |
Beard or mustache | Facial hair can harbor lice |
Eyelashes or eyebrows | More often seen in children |
If a child has lice on their eyelashes or eyebrows, it deserves special attention, which is explained in the complications section below.
How Do You Get Pubic Lice?
Pubic lice spread from the hair of one person to the hair of another. The most common route is during sex, when crabs move directly from one partner's pubic hair to the other's.
A less common but still real route is indirect contact. Lice can survive on sheets, blankets, towels, and clothing for a short time, so sharing these items with someone who has pubic lice can pass them along.
Route | How common |
|---|---|
Close sexual contact | The most common way pubic lice spread |
Shared bedding, towels, or clothing | Less common, but possible |
When Should You See a Doctor?
Most cases resolve with over-the-counter treatment, but several situations call for professional care.
People with pubic lice should see a healthcare professional to check for other sexually transmitted infections, since the same contact that transmitted the lice may have transmitted something else. Children with pubic lice need a medical evaluation as well.
Seek medical advice specifically if any of the following apply:
Situation | Why it matters |
|---|---|
You are not sure you have crabs | A doctor can confirm or rule out the diagnosis |
Over-the-counter products do not kill the lice | Stronger prescription treatments may be needed |
You are pregnant | Some medicines are not safe during pregnancy or breastfeeding |
Skin sores are infected from scratching | Infected sores may need separate treatment |
The special concern with children deserves emphasis. Pubic lice on a child may be a sign of sexual abuse, so any child found to have pubic lice needs to be evaluated by a healthcare professional to check for abuse.
What Are the Possible Complications?
Left untreated or repeatedly scratched, pubic lice can lead to a few complications beyond the itching itself.
Complication | Details |
|---|---|
Discolored skin | Pale blue spots can appear where lice have been feeding; these may be harder to see on Black or brown skin |
Infections from scratching | Repeated scratching of itchy bites can cause the sores to become infected |
Eye irritation | Children with lice on their eyelashes may develop a form of pink eye, called conjunctivitis |
These complications are treatable, but they are easier to avoid entirely with prompt treatment and less scratching.
How Is Pubic Lice Diagnosed?
Diagnosis is simple and visual. You or a healthcare professional can usually tell pubic lice are present by looking at the genital area.
Seeing moving lice confirms the diagnosis of pubic lice.
It is worth understanding one diagnostic nuance: lice eggs, called nits, may suggest an infestation, but nits can continue to cling to hairs even after they die from treatment. In other words, finding nits after treatment does not automatically mean the lice survived. The presence of moving lice is what confirms an active infestation.
How Are Pubic Lice Treated?
Treatment follows a clear ladder, starting with products you can buy without a prescription and moving to stronger options if needed.
First Step: Over-the-Counter Lotions and Shampoos
Treatment for pubic lice most often begins with permethrin or pyrethrin products. These are lotions and shampoos made to kill lice, available without a prescription. You apply the product to the genital area and follow the package directions closely, repeating treatments as directed — often in 7 to 10 days.
If only a few live lice and nits remain after treatment, they can often be removed with a nit comb or your fingernails.
Prescription Options
If over-the-counter treatment does not clear the lice, a healthcare professional may prescribe stronger treatments.
Prescription option | How it works | Important notes |
|---|---|---|
Malathion lotion | Applied to the area with lice and washed off after 8 to 12 hours | Prescription-strength topical treatment |
Ivermectin (Stromectol) | Taken as a single dose of two pills | A second dose can be taken in 7 to 10 days if needed; do not take if pregnant or breastfeeding |
Eyelash and eyebrow treatment | Petroleum jelly applied with a cotton swab at night, washed off in the morning | May need to be repeated for a few weeks; keep out of the eyes |
How to Prevent Reinfestation
Successful treatment involves more than applying medicine. Three steps work together to end the infestation completely.
Step | What to do |
|---|---|
Check all hairy areas | Lice can move away from treated areas to other hairy body parts, so check and treat everything |
Wash bedding, clothing, and towels | Launder items used in the 2 to 3 days before treatment in hot, soapy water at least 130°F (54°C), then dry on the hottest setting for at least 20 minutes |
Handle items you cannot wash | Dry-clean them or seal them in an airtight bag for two weeks |
And perhaps the single most important step: sexual partners of anyone treated for pubic lice also need treatment. If a partner is not treated, the lice will likely come right back.
How Can Pubic Lice Be Prevented?
Prevention comes down to one simple principle: avoid the routes of transmission.
To keep from getting pubic lice, do not have sex or share bedding or clothes with anyone who has them.
What to Expect at the Doctor
If you cannot get rid of pubic lice on your own, a healthcare professional can help. Preparing for the appointment goes faster if you write down answers beforehand. Useful things to have ready include how long you have had pubic lice, your symptoms, how you may have gotten them, whether you have had sex or shared sheets or towels since finding them, what treatments you have already tried, any long-term health conditions, and all medicines, vitamins, and supplements you take, including dosages.
During the visit, expect a physical exam in which the healthcare professional checks the genital area for live lice or live lice eggs (nits).
Conclusion
Pubic lice may carry an awkward reputation, but they are a common, easily recognized, and highly treatable condition. The itching is intense, the insects are tiny, and the spread is simple to understand — and the fix is just as straightforward: an over-the-counter permethrin or pyrethrin treatment, thorough hot-water laundering of bedding and clothing, checking every hairy area of the body, and making sure every sexual partner is treated too. With those steps done together, crabs can be eliminated completely.
Pubic lice are one of several contagious skin infestations spread by close contact — explore our related guide on Scabies for another condition with a similar treatment approach.
*This guide is for general information only and is not a substitute for professional medical advice. Always consult a qualified healthcare provider for diagnosis and treatment.*
Frequently Asked Questions
What exactly are pubic lice?
Pubic lice (crabs) are tiny crab-shaped insects, 1/16 inch (1.6 mm) or smaller, that live in genital hair, feed on blood, and cause intense itching. They are a different species from head lice and body lice.
How do you get pubic lice?
Most often through close sexual contact, when lice move from one partner's pubic hair to another's. Less commonly, they spread through shared bedding, towels, or clothing.
Can pubic lice spread beyond the genital area?
Yes. They can move to any thickly haired body area, including the legs, chest, armpits, beard, and mustache. In children, they more often appear on eyelashes and eyebrows.
What are the main symptoms?
Intense itching in the genital area is the hallmark sign. Visible moving lice and small eggs (nits) clinging to hair shafts confirm the infestation, and pale blue spots may appear where lice have fed.
How are pubic lice diagnosed?
By visual inspection — seeing moving lice in the genital area confirms the diagnosis. Nits alone are not proof of an active infestation, since dead nits can cling to hair even after successful treatment.
What is the first-line treatment?
Over-the-counter lotions or shampoos containing permethrin or pyrethrin, applied to the genital area as directed on the package and repeated as needed. A nit comb or fingernails can remove leftover nits.
What if over-the-counter treatment does not work?
A doctor can prescribe malathion lotion, oral ivermectin (two pills, not safe during pregnancy or breastfeeding), or nightly petroleum jelly for lice on eyelashes and eyebrows.
Why do sexual partners need treatment too?
Pubic lice spread through close contact between partners, so an untreated partner will reinfest the treated one. All partners must be treated at the same time, along with washing bedding and clothing in hot water at 130°F (54°C) or higher.
What This Guide Is Based On
Specialist-reviewed hospital clinical guidance on pubic lice (pediculosis pubis), updated December 2025, alongside the peer-reviewed chapter on lice in Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases (10th edition, 2026), UpToDate clinical overviews on pediculosis pubis and ciliaris, and patient education from the American Sexual Health Association.
References
Pubic lice (crabs) — Symptoms & causes — Mayo Clinic, updated December 18, 2025.
Pubic lice (crabs) — Diagnosis & treatment — Mayo Clinic, updated December 18, 2025.
Additional references consulted:
Blaser MJ, et al., eds. Lice (pediculosis). Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 10th ed., Elsevier, 2026.
Goldstein AO, et al. Pediculosis pubis and pediculosis ciliaris. UpToDate, accessed September 10, 2025.
American Sexual Health Association, Crabs: Fast facts, accessed September 10, 2025.
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