Finding head lice takes patience, good lighting, and the right comb. Adult lice are only about the size of a sesame seed and move quickly through hair, which is why a careful, systematic search works far better than a casual glance at the scalp. Here’s how to check thoroughly and know exactly what you’re looking for.
What Lice and Nits Actually Look Like
Before you start searching, it helps to know what you’re trying to spot at each life stage. Eggs (called nits) are tiny, just 0.8 mm by 0.3 mm, oval-shaped, and usually yellow to white. They’re glued firmly to individual hair shafts, typically within a quarter inch of the scalp. Nymphs, the newly hatched lice, are roughly the size of a pinhead. Adults grow to about the size of a sesame seed, have six legs with claws, and range from tan to grayish-white. In people with dark hair, adult lice often appear darker.
One of the most common sources of confusion is telling nits apart from dandruff. The simplest test: try to flick or pull the white speck off the hair strand. Dandruff slides off easily. Nits don’t. They’re cemented to the shaft and resist removal. You may also encounter “pseudonits,” which are small tubes of dead skin cells (keratin casts) that wrap loosely around the hair. These tend to be irregularly shaped and slide along the strand, while real nits are oval and fixed in place.
Where to Look First
Lice gravitate toward the warmest parts of the scalp. You’ll most often find nits on hair behind the ears and near the back of the neck. These are the best places to start your inspection. If someone has been scratching, you may also notice small red bumps or sores on the scalp, neck, and shoulders. On darker skin tones, these bumps can be harder to see. Itching is the most common symptom of an infestation, but it can take weeks to develop after the first exposure, so don’t rely on itching alone as a sign.
Tools You Need
A fine-toothed metal lice comb is essential. Look for one with teeth spaced less than 0.3 mm apart, which is narrow enough to catch both adult lice and the smallest nits. Plastic combs from drugstore kits are often too wide to trap nymphs reliably. Beyond the comb, gather a few other supplies: a bright lamp, a magnifying glass if you have one, a spray bottle of water, hair clips or bobby pins, a regular comb for detangling, a towel, tissues, and a disposable bag for wiping off what the comb collects.
Step-by-Step Detection
Sit the person under a bright light and drape a towel over their shoulders. Start by combing out tangles with a regular comb so the fine-toothed lice comb can pass through smoothly. Keep the hair slightly damp with a spray bottle, which slows lice down and makes them easier to catch.
Part the hair into four sections. Work through only one section at a time. Within each section, lift a strand about one inch wide and no more than half an inch thick. Place the teeth of the lice comb as close to the scalp as possible, pressing them deeply into the base of the strand. Comb slowly and firmly from the scalp all the way to the tip of the hair.
After each stroke, wipe the comb onto a white tissue or paper towel. This is where you’ll actually see what you’ve caught. Nits will look like tiny pale specks stuck to hair strands on the tissue. Live lice, if present, will be small brown or tan insects that may still be moving. Using a white surface makes both far easier to spot than trying to examine them in the hair itself.
Once a strand is clear, pin it up and away from the unchecked hair to avoid cross-contamination. Repeat this process through all four sections. After checking the entire head, rinse the hair thoroughly with plain water.
Dry Combing vs. Wet Combing
There’s ongoing debate about whether to comb through wet or dry hair. Wet combing with conditioner is the traditional recommendation, but it has drawbacks: when hair is slick with product, it’s harder to see whether you’ve actually removed lice or nits from the comb. Dry combing allows you to monitor your progress more clearly, and it can be repeated as often as needed without having to wash and dry the hair each time. In a small case series published in The Lancet, dry combing cleared lice within a week across all ten infestations tested, with no recurrence from hatching nits.
A practical middle ground is to dampen the hair lightly with water (no conditioner) during detection. This slows the lice enough to catch them while still letting you see what’s on the comb.
Signs You’ve Found an Active Infestation
Finding a live, crawling louse is the clearest confirmation. Finding nits alone requires a bit more interpretation. Nits found within a quarter inch of the scalp are likely viable, meaning they could still hatch. Nits found further from the scalp, more than a quarter inch out along the hair shaft, are generally either already hatched (empty casings) or dead. This is why both the American Academy of Pediatrics and the National Association of School Nurses recommend against “no-nit” policies in schools. Nits stuck to hair are very unlikely to transfer to another person, and misdiagnosis by non-medical professionals is extremely common.
If you find only a few nits far from the scalp and no live lice after a thorough comb-through, you may be looking at the remnants of an old, already-resolved infestation rather than an active one.
How Often to Recheck
A single check can miss newly laid eggs or tiny nymphs. If you suspect exposure or found nits during your first pass, repeat the full comb-through every three to four days for at least two weeks. This schedule catches any nymphs that hatch from eggs you may have missed, since nits take about seven to ten days to hatch. Consistent rechecking over two weeks covers the full life cycle and gives you confidence that the infestation is truly gone.