Crabs (pubic lice) are treated with an over-the-counter lice medication: 1% permethrin lotion or a pyrethrins-with-piperonyl-butoxide mousse applied to the pubic hair and other affected areas, then repeated in 9–10 days if live lice remain CDC treatment guidance. Treat all recent partners, and wash bedding and clothing in hot water.
with the right treatment
testing, not symptoms, decides
| Item | Value |
|---|---|
| Curable? | yes — with the right treatment |
| Tested by | exam + lab |
| Often | no symptoms |
| If you may have it | get tested — testing, not symptoms, decides |
How crabs are treated
Pubic lice are Pthirus pubis, small blood-feeding insects that grip coarse hair and lay eggs (nits) cemented to the shaft CDC, About Pubic Lice. You kill them with a topical insecticide the lice absorb. The first-line choice is over the counter: either a 1% permethrin lotion or a mousse combining pyrethrins with piperonyl butoxide, a compound that boosts the pyrethrins' effect.
Apply the medication to the pubic hair and any other areas with lice, leave it on for the time the label states, then rinse it off. These treatments kill live lice more reliably than unhatched eggs, so repeat the application in 9–10 days if you still see live lice. That second round catches anything that hatched after the first CDC STI Treatment Guidelines.
Crabs can spread beyond the groin to the armpits, chest, beard, and sometimes the eyelashes. Coarse-hair sites elsewhere on the body are treated the same way as the pubic area. The eyelashes are the exception: for lashes you do not use insecticide near the eye. See the dedicated guidance on crabs in eyebrows, eyelashes & other body hair for how those areas are handled.
Permethrin vs. pyrethrins — which to choose
| Option | Active ingredient | How it's used | Repeat? |
|---|---|---|---|
| Permethrin lotion | 1% permethrin | Applied to affected hair, left on per label, then rinsed | In 9–10 days if live lice remain |
| Pyrethrins mousse | Pyrethrins + piperonyl butoxide | Applied to affected hair, left on per label, then rinsed | In 9–10 days if live lice remain |
| Eyelash infestation | Ophthalmic-grade petrolatum | Smothers lice on the lashes — no insecticide | Continued until lashes clear; see a clinician |
Both topical options are reasonable starting points. Pyrethrins come from chrysanthemum flowers, so people with a known ragweed or chrysanthemum allergy should be cautious. Follow the package directions exactly. Leaving a product on too long doesn't help and can irritate the skin.
What treatment is actually like
This is a short course you can do at home. Apply the lotion or mousse, wait, rinse, and check the hair for live lice over the following days. After treatment, dead and remaining nits often stay stuck to the hair shafts. Combing them out with a fine-toothed comb helps you tell old, empty egg cases from a new infestation.
A crabs diagnosis is common and treatable, and clinics deal with it routinely. If you're not certain what you're looking at, review the crabs symptoms first, and if you want confirmation before treating, the how to test & diagnose crabs at home guide walks through identifying lice and nits.
On the same day you treat your body, decontaminate the things lice touched: machine-wash and hot-dry any bedding, towels, and clothing used in the prior 2–3 days. Items you can't wash can be sealed in a plastic bag for two weeks. You don't need to fumigate your home or shave, since lice live on hair and don't survive long on surfaces.
Common mistakes
- Skipping the second application when live lice are still present, which lets eggs the first round missed hatch later.
- Treating yourself but not your partner, so the lice bounce back and forth.
- Using regular petroleum jelly or insecticide on the eyelashes instead of ophthalmic-grade petrolatum.
- Mistaking leftover empty nits for an active infestation and over-treating irritated skin.
Partner treatment
Crabs spread mostly through close sexual contact, so treating only yourself usually isn't enough. Tell every sex partner from the past month so they can be treated at the same time, and avoid sexual contact until both of you have completed treatment and are clear CDC DPDx. Have your partner decontaminate their bedding and clothing too. Coordinating treatment keeps you from passing the lice back and forth. Ask your clinician or pharmacist whether a partner who has no symptoms still needs to treat.
Follow-up and when to retreat
There's no lab "test of cure" for pubic lice; the check is visual. A few days to about a week after treatment, look closely at the treated areas for live, moving lice. Itching can linger for a little while even after the lice are dead, because it's an allergic reaction to their bites, so itch alone doesn't mean treatment failed.
If you still find live lice, retreat with the same product on the 9–10 day schedule. If lice persist after a proper repeat treatment, that points to either reinfestation from an untreated partner or possible resistance to that medication; at that stage, see a clinician, who may prescribe an alternative. Because crabs are sexually transmitted, this is also a sensible moment to check your status for other infections. See when to test after exposure for the right timing and get tested when you're ready.
What happens if crabs go untreated
Pubic lice don't cause serious internal disease, but left alone they keep feeding and multiplying. The main consequences are persistent, sometimes intense itching; small bluish-gray spots or skin discoloration at the bite sites; and skin that becomes raw or infected from scratching (a secondary bacterial skin infection that may then need antibiotics). Untreated lice also keep spreading to other body hair on you and to anyone in close contact. The infestation won't clear on its own, so there's no benefit to waiting.
Preventing crabs going forward
Because crabs travel by skin-to-skin and hair-to-hair contact, condoms reduce but don't fully eliminate the risk, since lice can move across hair the condom doesn't cover. The most reliable prevention is clearing a current infestation in both you and your partner before resuming sexual contact, and not sharing bedding, towels, or clothing while anyone is being treated. Routine STI testing matters here too, since the same contact that passes lice can pass infections that have no symptoms; condoms used every time lower the risk for the sexually transmitted ones.
When to see a clinician
Self-treatment with an OTC product is appropriate for most uncomplicated cases. See a clinician if lice are on or near the eyelashes, if you're pregnant or breastfeeding, if the affected person is a young child, if live lice persist after a correct repeat treatment, or if the skin becomes painful, swollen, oozing, or shows signs of infection. A clinic can confirm the diagnosis, prescribe an alternative when the OTC route fails, and screen for other STIs at the same visit. Many health departments, Planned Parenthood, and Title X clinics offer this at free or low cost — you can compare testing providers to find one that fits.