Head lice are tiny, flat, wingless insects about the size of a poppy seed. In hair, they appear as dark specks that cling close to the scalp, while their eggs (called nits) look like tiny yellow or white dots glued to individual hair strands. Spotting them takes patience and the right technique, because lice move quickly and avoid light.
What Adult Lice Look Like
A fully grown head louse is roughly 2 to 3 millimeters long, about the size of a sesame seed. They have six legs, each ending in a small claw designed to grip hair shafts. Their bodies are flat and oval-shaped, making them hard to spot from above.
Color is one of the trickiest parts of identification. Lice are semi-translucent when they first hatch, then darken as they mature. An adult louse that has recently fed will look reddish-brown or dark brown because its body is filled with blood. On lighter hair, they can appear tan or grayish. On darker hair, they blend in almost perfectly, which is why combing them out onto a white paper towel or cloth is often easier than trying to spot them in place.
Lice do not jump or fly. They crawl, and they crawl fast. When you part the hair to look for them, they scatter away from the light toward the scalp. This is why a quick glance rarely reveals an infestation, even a heavy one.
What Nits Look Like on the Hair Shaft
Nits are lice eggs, and they’re usually the first sign people notice. They’re oval-shaped, extremely small (smaller than a pinhead), and cemented to one side of a hair strand with a glue-like substance the female louse secretes. This is the key visual detail: nits don’t slide freely along the hair. If you pinch a strand between your fingers and try to pull a speck down, a nit will resist. It stays put.
Live nits tend to be yellow or golden-brown and sit very close to the scalp, typically within a quarter inch. They need the warmth of the scalp to develop. After the louse inside hatches, the empty shell turns white or clear and may be found farther from the scalp as the hair grows out. Finding only white, empty nits far from the scalp could mean the infestation is old or already resolved. Finding yellow or brown nits close to the scalp is a stronger sign of an active problem.
Where to Look First
Lice tend to concentrate in the warmest areas of the scalp. The most common spots are behind the ears, along the nape of the neck, and under bangs near the forehead. If you’re checking someone’s head, start in these areas. Part the hair in small sections using a fine-toothed comb (often called a nit comb) and look at the base of the hair shafts under bright, direct light. A magnifying glass helps significantly, especially for spotting nits.
Work through the entire head in sections, wiping the comb on a white paper towel after each pass. Adult lice and nymphs (immature lice) will show up clearly against the white background. This wet-combing method, done on damp hair with a little conditioner to slow the lice down, is considered the most reliable way to confirm an infestation.
Nymphs: The In-Between Stage
After hatching, a louse goes through three nymph stages over about 9 to 12 days before reaching adulthood. Nymphs look like smaller, paler versions of adult lice. A freshly hatched nymph is barely visible to the naked eye and nearly transparent. By the second and third stages, it’s easier to see but still smaller than a full-grown louse. Because of their size and color, nymphs are the hardest life stage to spot visually. The fine-toothed comb is your best tool for catching them.
How to Tell Lice Apart From Dandruff
This is one of the most common sources of confusion. Both nits and dandruff can appear as small white or yellowish specks in the hair. The simplest test is movement. Dandruff is loose, flaky skin that slides easily along the hair or falls off when you shake your head. It often ends up on your shoulders, clothing, or bedding. Nits are stuck firmly in place and won’t budge without deliberate effort, usually requiring you to pull them along the strand with your fingernails or a nit comb.
Location matters too. Nits cluster close to the scalp, especially behind the ears and at the nape. Dandruff can appear anywhere on the head or hair. If you find a white speck several inches from the scalp that slides off easily, it’s almost certainly dandruff or a hair product residue. A yellow or white speck cemented near the root of the hair is more likely a nit.
Shape is another clue. Dandruff flakes are irregularly shaped pieces of skin. Nits are uniformly oval and attached at an angle to one side of the hair shaft. Under a magnifying glass, the difference becomes obvious.
Scalp Symptoms That Accompany Lice
Beyond what you can see in the hair, lice leave signs on the skin. The most common symptom is itching, caused by an allergic reaction to louse saliva injected during feeding. This itching is most intense behind the ears and at the back of the neck. It can take several weeks after the initial infestation for the allergic response to develop, which means you can have lice for a while before feeling any itch at all.
Persistent scratching can break the skin and create small red sores on the scalp. These sores sometimes pick up bacteria normally present on the skin, leading to a secondary infection with crusting or oozing. If you notice sores along with the specks in the hair, that’s a strong indicator of an active, established infestation rather than a recent one.
What an Active Infestation Looks Like vs. an Old One
The difference between a current infestation and a past one comes down to what you find alive. A live, crawling louse or nymph on the scalp confirms an active case. Live nits (yellow-brown, close to the scalp) also point toward an ongoing problem. Empty nit shells (white, farther from the scalp) without any live lice or fresh nits suggest the infestation may have already run its course or been treated.
This distinction matters because many children are unnecessarily kept home from school over empty nit shells that pose no risk. If you’re unsure whether what you’re seeing is active, the wet-combing method over several days will give you a definitive answer. Comb through damp hair with a nit comb every two to three days for about two weeks. If you’re consistently finding nothing alive on the paper towel, the infestation is likely over.