Head lice are tiny, flat, wingless insects roughly 2 to 3 mm long, about the size of a sesame seed. They range in color from white to brown to dark gray, and they darken after feeding on blood from the scalp. At any given time, you might spot adult lice, smaller baby lice called nymphs, or their eggs (called nits) glued to individual hair strands. Here’s what each stage looks like and how to tell them apart from dandruff or other debris.
What Adult Lice Look Like
An adult louse has six legs, each tipped with a small claw that grips hair shafts. The body is elongated and flat, making it easy for the insect to stay pressed close to the scalp. Before feeding, lice tend to appear lighter, closer to tan or grayish-white. After a blood meal, their bodies darken to a reddish-brown because you can see the blood through their semi-transparent exoskeleton.
Despite being visible to the naked eye, adult lice are fast. They crawl quickly through hair and avoid light, which is why you’re more likely to spot them behind the ears and along the nape of the neck, where hair is thicker and warmer. They cannot jump or fly.
What Nymphs Look Like
Nymphs are baby lice that have just hatched from eggs. They look like smaller versions of adults, about the size of a pinhead, and are often pale or nearly translucent. Because of their size, they’re significantly harder to see without magnification. Nymphs mature into full-sized adults in about seven days, growing darker and more visible as they develop.
What Nits Look Like
Nits are the oval-shaped eggs that female lice cement onto individual hair strands. They’re roughly 1/30 of an inch long, about the size of a pinhead, and appear yellow or white when they contain a developing embryo. After hatching, the empty shell stays attached to the hair and looks more white or clear.
Location on the hair shaft is the most useful clue for determining whether nits are alive. Adult females lay eggs within 1/4 inch of the scalp, where body heat helps them incubate. Nits found more than 1/4 inch from the scalp have likely already hatched or died. Nits more than 1/2 inch from the scalp are almost always empty shells that have simply grown out with the hair over time.
One defining feature of nits: they don’t slide off easily. Each egg is glued to the hair with a cement-like substance the female produces. If you try to pull a nit along the hair shaft, it resists. This is one of the quickest ways to distinguish a nit from a flake of dandruff or hair product buildup.
Lice vs. Dandruff
Dandruff flakes and lice eggs look surprisingly similar at first glance, both appearing as small white or yellowish specks in the hair. But a few differences make identification straightforward once you know what to check.
- Movement when touched: Dandruff flakes brush away easily with a finger or comb. Nits stick firmly to the hair and require pinching or sliding with your fingernails to remove.
- Shape: Dandruff flakes are irregular and flat. Nits are uniformly oval, teardrop-shaped, and attached at an angle to one side of the hair strand.
- Location: Finding a white or yellow speck very close to the scalp is more suggestive of lice. The farther from the scalp you find it, the more likely it’s dandruff, though dead nits can also appear further out as hair grows.
If you’re unsure, a magnifying glass can make the difference obvious. Under magnification, a nit has a distinct capsule shape with a small cap on one end, while dandruff looks like an irregularly shaped skin flake.
Where to Look on the Head
Lice prefer warm, sheltered areas of the scalp. The most common spots to find both live lice and nits are behind the ears and along the back of the neck at the hairline. These areas stay warm and give lice easy access to the skin for feeding. When checking for lice, part the hair in small sections in these zones first before working through the rest of the scalp.
How to Spot Lice More Easily
Visual inspection alone often misses lice, especially light infestations, because the insects move quickly away from disturbance. Wet combing is significantly more accurate. The process involves wetting the hair, applying a thick conditioner, and then combing from roots to ends with a fine-toothed lice comb. The conditioner slows the lice down and makes it harder for them to grip the hair.
After each pass of the comb, wipe the conditioner onto a white paper towel or tissue. Against the white background, live lice and nymphs become much easier to see, even the tiny translucent ones. Nits will also appear on the comb’s teeth. This method works better than dry visual checks because lice can outrun your parting fingers in dry hair but get trapped in conditioner.
What Lice Bites Look Like
Lice feed by biting the scalp and drawing small amounts of blood several times a day. The bites themselves are tiny and often not visible, but the scalp’s allergic reaction to lice saliva produces itching. Over time, repeated scratching can cause small red bumps, sores, or scabs on the scalp, particularly behind the ears and at the nape of the neck. In some cases, scratching can lead to a secondary bacterial infection, which may look like crusted or oozing patches on the skin. The itching itself sometimes doesn’t start for weeks after an infestation begins, so the absence of itching doesn’t rule out lice.