The most reliable way to check for lice is wet combing with a fine-toothed metal nit comb, which is nearly four times more effective at finding live lice than looking through dry hair with your eyes alone. A visual scan might spot nits (eggs), but it frequently misses the live insects that confirm an active infestation. Here’s how to do a thorough check at home.
What You’re Looking For
Adult head lice are about 2 to 3 mm long, roughly the size of a sesame seed. They’re tan, brown, or black, and they move quickly through hair while actively avoiding light. That speed and light-avoidance is exactly why they’re so easy to miss during a casual glance.
Nymphs (newly hatched lice) are about the size of a pinhead. They look like smaller versions of adults and are even harder to spot. Nits, the eggs, are teardrop-shaped and white or yellow, glued firmly to individual hair shafts close to the scalp. Empty nit casings turn translucent or gray. Viable eggs are almost always found within about 6 mm of the scalp, because they need body heat to survive.
Nits vs. Dandruff
Nits are one of the most commonly misidentified things in hair. Dandruff flakes, hairspray droplets, and dirt particles can all look similar at first glance. The key difference is attachment: nits are cemented to the hair shaft and won’t budge if you brush them with your finger or a regular comb. Dandruff flakes sit loosely on the scalp and fall off easily. Dandruff also tends to be larger, sometimes greasy-looking, and it sheds from the scalp itself rather than clinging to the hair. Nits have a distinct teardrop shape, while dandruff is flat and irregular.
Gather Your Supplies
You need three things: a metal nit comb with long, closely spaced teeth (skip plastic combs, which have wider gaps that let nits and small lice slip through), a good light source, and something to wipe the comb on between passes, like a white paper towel or white cloth. The white background makes it much easier to spot tiny lice.
For lighting, natural light near a window works best because nits actually reflect ultraviolet light and become easier to see in sunlight. If that’s not practical, use a lamp with at least a 60-watt bulb or a bright LED flashlight. A magnifying glass can help, especially if your eyesight isn’t sharp at close range or if the person you’re checking has hair that’s a similar color to the lice.
Where to Focus on the Scalp
Lice don’t distribute evenly across the head. They cluster in warm spots where they can feed easily. Concentrate your search on four areas: the crown of the head, the bangs, behind both ears, and the nape of the neck. These are the zones where you’ll find the highest density of both live lice and nits. If you’re going to find evidence of an infestation anywhere, it will almost certainly be in one of these spots.
The Wet Combing Method
Wet combing is the gold standard for home detection. In a large study comparing methods, visual inspection found live lice on only about 7% of infested children, while detection combing found live lice on 21%. That means dry visual checks missed roughly two out of every three active cases.
Start by wetting the hair thoroughly and applying a generous amount of regular conditioner. The conditioner slows the lice down (they can’t run as fast through slippery hair) and makes the comb glide without pulling. Section the hair into small, manageable parts using clips. Starting at the scalp, draw the nit comb slowly from root to tip through each section. After every pass, wipe the comb on your white paper towel or cloth and look for anything caught in the teeth: tiny insects, nymphs, or the oval nits.
Work systematically across the entire head so you don’t accidentally skip a section. Pay extra attention to those four hot spots (crown, bangs, behind ears, nape of neck), but comb everywhere. The whole process takes about 15 to 20 minutes on shoulder-length hair.
How to Tell If the Infestation Is Active
Finding nits alone doesn’t necessarily mean you have an active problem. Nits take about 8 to 9 days to hatch after they’re laid. Because the female louse lays eggs right at the base of the hair shaft, nits found close to the scalp (within a quarter inch) are more likely to be viable. As hair grows out, old nit casings travel further from the scalp. If the only nits you find are more than a quarter inch from the scalp and you see no live lice or nymphs, the infestation is likely old and already resolved.
An active infestation is confirmed when you find at least one live louse or nymph. This is another reason wet combing matters so much: it gives you a definitive answer rather than leaving you guessing about whether those white specks near the hairline are eggs or dandruff.
Checking Multiple People
If you find lice on one person in your household, check everyone who lives there. Lice spread through direct head-to-head contact, which is why they move so efficiently through families and classrooms. Use the same wet combing method for each person, and clean or replace the comb between checks. Rinse it in hot water (at least 130°F) for a few minutes to kill any lice or eggs clinging to the teeth.
For ongoing monitoring during or after treatment, repeat the wet combing check every few days for two to three weeks. This catches any nymphs that hatch from eggs that survived the initial treatment before they mature enough to lay new eggs themselves.