The most reliable sign of pubic lice, commonly called crabs, is persistent itching in the groin area combined with the visible presence of tiny lice or their eggs attached to coarse body hair. The itching typically begins anywhere from 5 days to several weeks after exposure, which means you may carry an infestation for a while before noticing anything wrong.
What Pubic Lice Look Like
Adult pubic lice are 1.1 to 1.8 mm long, roughly the size of a pencil tip. They’re short, flat, and noticeably wider than the head lice most people picture. Under good lighting, they look pale gray or tan and have a rounded, crab-like shape, which is where the nickname comes from. They grip tightly to hair shafts and don’t move quickly, so you’re more likely to spot one sitting still than crawling around.
Nits, the eggs laid by adult lice, are even smaller. They appear as tiny oval specks attached firmly to individual hairs, usually close to the skin. They can be white, yellowish, or slightly translucent. Unlike dandruff or skin flakes, nits don’t brush off easily. They’re essentially glued to the hair shaft. Both lice and nits are visible to the naked eye, but a magnifying glass makes identification much easier, especially if only a few lice are present.
The Symptoms You’ll Notice First
Itching is the hallmark symptom, and it tends to be worst at night. The itch comes from your body’s allergic reaction to lice saliva as they feed on small amounts of blood. During the first infestation, it can take days or weeks for your immune system to develop that reaction, so the absence of itching doesn’t guarantee you’re in the clear. People who’ve had crabs before may start itching within a day or two of re-exposure because their immune system already recognizes the allergen.
Beyond itching, you may notice small blue-gray spots on the skin in affected areas. These spots, sometimes called sky-blue spots, develop at bite sites where a component of lice saliva reacts with blood beneath the skin. They’re painless and don’t raise above the surface. They’re easy to overlook but are a distinctive marker of pubic lice that you won’t see with other common skin irritations. Some people also develop mild redness, irritation, or tiny spots of dried blood on their underwear from scratching or from the bites themselves.
How to Check Yourself
You’ll need good lighting and ideally a magnifying glass. Pubic lice infestations can involve very few lice, sometimes just a handful, which makes them easy to miss in a quick glance. The lice attach themselves to coarse hair and often grip more than one hair at a time, anchoring in place.
Start by examining the pubic hair closely, parting it with your fingers and looking at the base of the hair shafts near the skin. Look for both the lice themselves and nits stuck to hairs. Pay attention to the entire groin area, including the inner thighs and the skin around the anus. Despite the name, pubic lice aren’t limited to the pubic region. They can also infest other areas of coarse body hair: armpits, chest hair, beards, mustaches, eyebrows, and even eyelashes. If you have symptoms in any of these areas, check them too.
If you see crawling lice, that confirms an active infestation. If you don’t see any moving lice but find nits firmly attached to pubic hair, that still strongly suggests an infestation that needs treatment. Nits alone in the pubic region are considered enough evidence to act on.
What Crabs Can Be Confused With
Several conditions cause itching in the groin, and not all of them are lice. Jock itch, a fungal infection, causes redness and itching but produces a spreading rash with defined borders rather than bite marks or visible insects. Contact dermatitis from new soaps, detergents, or fabrics causes more generalized redness and irritation. Folliculitis, infection of hair follicles, creates small red bumps that can look like pimples.
The distinguishing factor is always the presence of lice or nits on the hair. No other groin condition produces tiny organisms visibly clinging to hair shafts. If you’re itching but can’t find any lice or eggs after a thorough inspection with a magnifying glass, something else is likely going on.
How Crabs Spread
Pubic lice spread primarily through direct skin-to-skin contact during sexual activity. They crawl from one person’s body hair to another’s. Unlike head lice, they don’t jump or fly. Transmission through shared bedding, towels, or clothing is possible but far less common, because pubic lice depend on human body heat and blood to survive. Away from a human host, they die within one to two days.
Condoms do not prevent transmission. The lice live on skin and hair outside the areas a condom covers. Having crabs doesn’t mean you or your partner did anything wrong. It simply means close physical contact occurred with someone who had an active infestation, and lice are indiscriminate about whose hair they grip.
Treatment and What to Expect
Over-the-counter treatments are the standard first step. A 1% permethrin cream rinse, applied to the affected area and washed off after 10 minutes, is one of the most widely recommended options. Another option is a pyrethrin-based product combined with piperonyl butoxide, also applied and washed off after 10 minutes. Both are available at most pharmacies without a prescription.
Before applying treatment, read the product instructions carefully. After the initial treatment, you’ll typically need a second application about 9 to 10 days later to kill any newly hatched lice that survived as nits during the first round. Nits are harder to kill than adult lice, so this follow-up matters.
You should also wash any clothing, bedding, and towels used in the two days before treatment in hot water (at least 130°F) and dry them on the hottest dryer setting. Items that can’t be washed can be sealed in a plastic bag for two weeks, which outlasts the lifespan of any lice or viable eggs. Sexual partners from the previous month should be notified and treated at the same time, even if they don’t have symptoms yet, to prevent passing the infestation back and forth.
If over-the-counter treatment doesn’t resolve the problem after two applications, or if lice are present on eyelashes, a healthcare provider can offer stronger prescription options. Eyelashes require a different approach because standard lice treatments should not be applied near the eyes.