Head lice are tiny, wingless insects that live on the human scalp. An adult louse is about the size of a sesame seed, roughly 2 to 3 millimeters long, with a flat, oval body and six legs. They can be tan, whitish-gray, or dark brown, and their color often shifts to blend with the host’s hair, making them surprisingly hard to spot.
What Adult Lice Look Like
A fully grown louse has a flat, elongated body with six legs that end in small claws designed to grip hair strands. Place one next to a sesame seed and they’re nearly identical in size. Their color ranges from pale tan to dark brown, and lice on darker hair tend to appear darker than those on blonde or light hair. This color-matching is a survival adaptation, not a perfect camouflage, but it’s effective enough to make visual detection tricky without careful searching.
Lice cannot fly or jump. They crawl, and they crawl quickly. Part the hair to look at the scalp and an adult louse will scurry away from the light, which is why many people never see a live one even during an active infestation. A fine-toothed lice comb run through wet hair is far more reliable than a visual scan alone.
What Nits (Eggs) Look Like
Nits are the eggs lice attach to individual hair strands, usually within a quarter inch of the scalp where body heat keeps them warm enough to develop. They’re extremely small, about the size of a knot in thread, and have a teardrop shape visible to the naked eye if you look closely. Live nits are typically white or yellowish-brown. After the egg hatches, the empty casing stays glued to the hair and turns more translucent or gray.
The most common places to find nits are behind the ears and along the neckline at the back of the head. These warmer areas of the scalp are preferred egg-laying sites. As hair grows, old nit casings move farther from the scalp. Finding nits more than a quarter inch from the scalp usually means they’ve already hatched or are no longer viable.
What Baby Lice (Nymphs) Look Like
When a nit hatches, it releases a nymph, a baby louse that looks like a smaller, paler version of an adult. A freshly hatched nymph is about the size of a pinhead. It goes through three molts over roughly seven days before reaching full adult size. During this stage, nymphs are nearly transparent, which makes them even harder to see than adults. They stay close to the scalp because they need to feed on blood multiple times a day to survive.
Lice vs. Dandruff: How to Tell the Difference
Nits and dandruff flakes can look similar at first glance, since both appear as small white or yellowish specks near the scalp. The simplest test is to try to flick or pull the speck off the hair. Dandruff flakes fall away easily because they sit loosely on the scalp and hair surface. Nits don’t budge. They’re cemented to the hair shaft with a glue-like substance that resists normal brushing and even vigorous scratching.
Shape is another reliable clue. Nits are teardrop-shaped and attached at an angle to a single strand of hair. Dandruff flakes are irregular, often larger than nits, and sometimes look greasy or waxy. Dandruff also affects the scalp itself, producing visible flaking skin, while nits are found exclusively on the hair strand, not the skin.
Other things commonly mistaken for nits include hair spray residue, dirt particles, and dried hair product. All of these slide off the hair easily when pulled. If a white speck resists removal and has that distinctive teardrop shape, it’s likely a nit.
Where to Look on the Head
Lice and nits concentrate in specific zones. The area behind both ears and the base of the skull at the neckline are the most productive spots to check. These regions stay warm and are close to the skin’s surface, which makes them ideal for lice to feed and lay eggs. In heavier infestations, nits can spread throughout the entire head of hair, and lice occasionally appear on eyebrows and eyelashes, though this is less common.
Good lighting matters. Natural daylight or a bright lamp angled toward the scalp makes lice and nits easier to spot. Wetting the hair first slows live lice down, giving you a better chance of seeing them before they crawl out of sight. Section the hair into small parts using clips and comb through each section with a fine-toothed nit comb, wiping the comb on a white paper towel after each pass. Against the white background, even tiny nymphs and nits become visible.
Color Variation Across Hair Types
Lice are not one fixed color. They range from nearly white to dark brown, and they can adapt their shade slightly over time to better match their host’s hair. In blonde or light hair, lice tend to appear lighter tan or almost translucent. In dark brown or black hair, they skew darker. Nits follow a similar pattern, sometimes taking on the color of the surrounding hair, though they’re most commonly white or pale yellow.
This color variation means lice are harder to spot in certain hair colors. People with blonde hair may find nits blend in more, while people with very dark hair might struggle to see the darker-bodied adults. In both cases, the nit comb and white paper towel method remains the most reliable detection approach, since it removes the guesswork of trying to distinguish a tiny insect from the hair around it.