The most reliable way to find out if you have lice is to comb through wet, conditioned hair with a fine-toothed detection comb and check what comes out on a white paper towel. Itching alone isn’t a reliable indicator, especially early on. It can take four to six weeks after an initial infestation for itching to even start, which means you could have lice for over a month without feeling a thing.
What You’re Looking For
Head lice go through three visible stages, and knowing what each looks like helps you tell the difference between an active infestation and an old one.
Adult lice are about the size of a poppy seed, gray or pale in color, and they move quickly through hair. They’re surprisingly hard to spot with the naked eye, especially in lighter hair. Nymphs (young lice) are even smaller and similarly dark.
Nits are the eggs, and they’re what most people notice first. They look like tiny white or yellowish-brown specks attached to individual hair strands close to the scalp, usually within about a quarter inch of the skin’s surface. Lice lay their eggs near the scalp because the eggs need warmth and a blood supply to develop. If you find nits more than a quarter inch from the scalp and no live lice, the infestation is likely old and no longer active.
The Slide Test: Lice vs. Dandruff
Nits get confused with dandruff constantly. The simplest way to tell them apart is to try moving the speck. Dandruff flakes slide easily off the hair shaft when you run your fingers through it or shake your head. Dandruff also tends to fall onto shoulders, clothing, and pillows. Nits don’t budge. They secrete a glue-like substance that cements them to the hair, so if you pinch a tiny white speck between your fingers and it won’t slide along the strand, that’s a strong sign it’s an egg and not dry skin.
The Wet Combing Method
Wet combing is the gold standard for home detection, with a sensitivity above 90%, meaning it catches the vast majority of infestations even when there are only a few lice present. A simple visual scan of dry hair catches about 80% to 90% of cases, but it’s easier to miss low-level infestations that way, especially if lice scatter when you part the hair.
Here’s how to do it properly:
- Gather your supplies first. You need a fine-toothed metal lice comb (with teeth spaced less than 0.3 mm apart), regular conditioner or detangling spray, white paper towels or tissues, a bowl of hot water for rinsing the comb, and hair clips for sectioning. A standard hair comb won’t work because the teeth are too far apart to catch nits or nymphs.
- Wash and condition the hair. Use ordinary shampoo, then apply a generous amount of any conditioner. The conditioner slows the lice down and makes it much harder for them to grip the hair and run, which is what they normally do when disturbed.
- Section the hair with clips. This keeps you organized so you don’t accidentally skip areas.
- Comb from root to tip. Place the comb flat against the scalp and draw it all the way through to the end of the hair. After each stroke, wipe the comb on a white paper towel and look for tiny dark specks (lice) or pale specks (nits). Rinse the comb in the bowl of hot water between strokes.
- Comb the entire head twice. Once through every section, then repeat the whole process a second time to catch anything you missed.
Expect the process to take about 10 minutes for short hair and 20 to 30 minutes for long, curly, or thick hair. If you’re checking a child, setting them up with a screen or book helps them sit still long enough.
Where To Focus Your Search
Lice don’t spread evenly across the scalp. They cluster in warm spots where hair is densest and closest to skin. The areas behind the ears, the temples, and the nape of the neck are where both live lice and nits concentrate most heavily. When doing a quick visual check, these are the three zones to examine first. Part the hair in small sections and look at the base of the hair shafts under good lighting. A magnifying glass helps, but bright natural light or a strong lamp aimed at the scalp works well on its own.
Confirming an Active Infestation
Finding nits alone doesn’t necessarily mean you have an active case. Nits can remain glued to hair long after the lice are gone, gradually moving further from the scalp as the hair grows out. An active infestation means you’ve found at least one of the following: a live louse or nymph on the scalp or comb, or nits firmly attached within a quarter inch of the scalp. If the only nits you find are further out on the hair shaft, treatment probably isn’t needed.
This distinction matters because many schools and parents treat based on nits alone, which can lead to unnecessary product use and stress. A single live louse on the comb is a definitive answer. Nits close to the scalp are a strong signal. Old nits far from the scalp are leftovers.
Checking Again After Treatment
If you do find lice and begin treatment, wet combing on a specific schedule helps you confirm the infestation is actually clearing. The NHS recommends combing on days 1, 5, 9, and 13 to catch newly hatched lice before they’re old enough to lay eggs themselves. Then check again on day 17 to verify the hair is completely clear. Lice eggs take about 7 to 10 days to hatch, so this schedule is designed to intercept each new generation before it can reproduce.
Signs You Might Have Missed
Most people assume itching is the first clue, but as noted earlier, a first-time infestation can go weeks without any itch at all. The itching is an allergic reaction to lice saliva, and your body needs time to develop that sensitivity. People who’ve had lice before may start itching sooner because their immune system already recognizes the allergen.
Other signs to watch for include a tickling sensation of something moving in the hair, small red bumps on the scalp or neck from bites, and difficulty sleeping (lice are more active in the dark). If a child is scratching their head persistently or you notice irritability at bedtime, it’s worth doing a wet comb check even if you don’t see anything obvious at first glance.