Pubic lice (crabs) testing

Yes. Pubic lice spread primarily through close sexual contact — skin-to-body hair proximity during sex — and are classified as a sexually transmitted infection. They are not caused by bacteria or viruses like classic STIs; they are a parasitic insect infestation. Finding pubic lice doesn't mean you automatically have a bacterial or viral STI, but it does signal the kind of sexual exposure that warrants a comprehensive STI screen for chlamydia, gonorrhea, syphilis, and HIV at the same visit. The lice themselves are easily cured with OTC pediculicide; the co-occurring STIs they signal may be more medically significant.

No — this is a persistent myth without clinical basis. Pubic lice cannot survive long away from a human host (only 24–48 hours) and their hooked front legs are specifically adapted to grip coarse hair, not smooth hard surfaces like toilet seats, which their claws cannot hold onto. The CDC does not list toilet seats as a meaningful route of transmission. Essentially all infestations result from direct prolonged body-to-body skin contact during sexual activity, or from sharing bedding or clothing very recently used by an infested person.

No. Condoms protect the areas they cover but pubic lice live on pubic hair, thighs, groin, abdomen, and other hair-bearing body skin well outside the area a condom covers. Lice crawl between these hair-bearing areas during close body contact. Condoms remain valuable for preventing chlamydia, gonorrhea, HIV, herpes, and other STIs — and remain strongly recommended for all the other STIs they do prevent — but they will not protect against pubic lice.

No — not at all. Pubic lice infest anyone who has close sexual contact with an infested person, regardless of how often that person bathes, showers, or launders their clothes. Cleanliness and hygiene have no meaningful effect on transmission or infestation risk. The louse does not seek out dirty or unclean environments — it seeks coarse body hair and a warm human host. The stigma associating pubic lice with poor hygiene is medically unfounded and creates unnecessary shame that can discourage people from seeking treatment and notifying partners.

Buy an over-the-counter permethrin 1% cream rinse (Nix) or pyrethrin/piperonyl-butoxide product (RID, A-200) at any pharmacy for about $10–$25 without a prescription. Apply the product to all dry, affected hair areas (pubic hair, inner thighs, abdomen, or other affected coarse hair areas), leave on for 10 minutes, then rinse thoroughly. Repeat the same application in 7–10 days to kill lice that hatched from eggs after the first treatment — this second round is mandatory, not optional. Do not apply these products near the eyes, eyebrows, or eyelashes — seek clinical evaluation for eyelash infestation. Wash all bedding and worn clothing in hot water (≥130°F) and dry on high heat the same day as treatment.

Yes — both are essential or re-infestation is almost guaranteed. All sexual partners from the past month must treat at the same time and avoid sexual contact until all are confirmed clear after both treatment rounds. Even a partner without itching can be infested and will re-infest you within days. Simultaneously, wash all bedding, towels, and worn clothing in hot water (≥130°F / 54°C) and dry on high heat for at least 20 minutes, or seal items in a plastic bag for at least 72 hours to kill any lice or nits present off the body. Doing both the partner treatment and the laundry decontamination together on the same day is the only way to reliably break the infestation cycle.

Eyelash or eyebrow infestation is a special case requiring clinical management — standard OTC lice shampoos, permethrin, and pyrethrin products are NOT safe near the eyes and must not be applied there. The standard clinical approach is applying a thick layer of petroleum jelly (Vaseline) carefully to the eyelash base twice daily for approximately 10 days to smother lice and nits by occluding their breathing pores. A clinician may also prescribe oral ivermectin or ophthalmic alternatives. Physical removal of nits with fine-tipped tweezers is also helpful. See a clinician before attempting any eye-area treatment.

The first treatment kills living adult lice and nymphs but does not reliably destroy nit eggs — the eggs are physically resistant to the active ingredients in OTC pediculicides. Those eggs hatch in approximately 6–10 days, releasing a new generation of lice that the first treatment can no longer kill. A second application precisely 7–10 days later targets these newly hatched nymphs before they mature into reproducing adults and lay yet another batch of eggs — breaking the reproductive cycle. Skipping the second round is the single most common reason people believe pubic lice 'came back' when the eggs simply never died.

True permethrin or pyrethrin resistance in pubic lice is uncommon — most apparent treatment failures result from re-infestation by an untreated sexual partner, skipping the second round of treatment, or incomplete application to all affected areas. If live lice are still present after two correctly timed and applied OTC treatments and all partners have been treated, see a clinician. Prescription alternatives include malathion 0.5% lotion (applied for 8–12 hours; kills both lice and some nits; good efficacy against resistance) and oral ivermectin (two doses of 250 mcg/kg, 2 weeks apart; effective against both lice and nymphs).

Both are parasitic infestations transmitted by close contact, but they are caused by entirely different organisms with different presentations and treatments. Pubic lice (Pthirus pubis) are visible 1–2 mm insects that cling to coarse body hair — you can see the lice and nits if you look carefully. Itching is localized to hair-bearing areas. Scabies is caused by a microscopic mite (Sarcoptes scabiei) that burrows under the skin and causes intense, widespread itching — often with a rash on the wrists, finger webs, waistline, and genitals — with characteristic burrow tracks visible to an examiner. Scabies is not visible to the naked eye and involves a rash over a broad body surface rather than localized to hair areas. Treatments differ: scabies requires permethrin 5% cream applied from neck to toes, or oral ivermectin. A clinician can distinguish them quickly on examination.

If this is your first-ever pubic lice infestation, itching typically takes 5 days to several weeks to develop — the immune system needs time to sensitize to louse saliva before the allergic response (itch) begins. If you've had pubic lice before, you may react within 1–2 days of re-exposure because the immune system is already primed. During the entire pre-symptomatic window — which can last several weeks on a first infestation — you can spread lice to sexual partners without realizing you're infested. This is why treating all partners simultaneously matters, regardless of whether they currently have symptoms.

Adult pubic lice are approximately 1–2 mm long — roughly the size of a sesame seed. They have a wide, squat, distinctly crab-shaped body (much broader than the elongated body of a head louse) with six legs; the two front pairs end in large, strongly hooked claws specifically shaped to grip the widely-spaced shafts of coarse pubic hair. They are pale grayish to rust-colored and move very slowly — barely perceptibly. Nits (eggs) are oval, yellowish-white, approximately 0.8 mm long, and are cemented firmly to individual hair shafts within a few millimeters of the skin surface — they do not slide or shake off as dandruff does. A magnifying glass or a phone camera in macro mode makes lice and nits much easier to identify during self-examination.

Yes — multiple studies from STI clinics in the UK, Australia, and the US have documented a significant decline in pubic lice diagnoses over the past two to three decades. The leading explanation is the increasing prevalence of pubic hair removal through waxing, shaving, and laser depilation — removing the louse's habitat makes colonization impossible. Some researchers have jokingly described the Brazilian wax as a de facto pubic lice prevention method. Pubic lice still exist and still present at STI clinics, but they are considerably rarer than they were in previous decades. If you are exposed to a known infested partner, risk remains regardless of current prevalence trends.