Lice are tiny, flat, wingless insects that range from about the size of a pinhead to a sesame seed depending on their life stage. They’re tan to grayish-white, have six legs, and move by crawling (they can’t fly or jump). There are three types that live on humans, and each looks slightly different and shows up in different places on the body.
What Adult Lice Look Like
Adult head lice are roughly 2 to 3 millimeters long, about the size of a sesame seed. They’re grayish-white or tan, oval-shaped, and flat. You’ll typically spot them close to the scalp, especially behind the ears and near the neckline, though they move quickly and can be hard to catch in the act.
Body lice look very similar to head lice in shape and color but tend to be slightly larger. The key difference is where you’ll find them. Body lice live in the seams and folds of clothing rather than on skin or hair. You might occasionally see one crawling on the skin or feeding, but checking clothing seams is the most reliable way to confirm an infestation.
Pubic lice, often called “crabs,” are noticeably different in shape. They’re smaller (1.5 to 2 millimeters) and have two oversized front legs that resemble the pincher claws of a crab. They’re the same tan to grayish-white color as other lice and are found primarily in coarse body hair: the pubic area, and less commonly the armpits, chest hair, eyebrows, or eyelashes.
What Nits (Lice Eggs) Look Like
Nits are oval-shaped eggs that measure about 0.8 millimeters, roughly the size of a knot in thread. They attach firmly to individual hair shafts close to the scalp, usually within a quarter inch of the skin surface where warmth helps them incubate. This firm attachment is one of the easiest ways to tell them apart from dandruff. Dandruff flakes off easily when you brush or shake the hair, but nits stay stuck. You’ll need to slide them along the hair shaft with your fingernails or a fine-toothed comb to remove them.
The color of a nit tells you a lot about whether it’s alive, dead, or already hatched:
- Live nits range from white to yellow to pale brown. The darker a live nit gets, the closer it is to hatching.
- Dead nits that never hatched turn brown or black.
- Empty casings left behind after hatching are white, gray, or translucent. These tend to sit farther from the scalp, a quarter inch or more away, because the hair has grown out since the egg was originally laid.
What Baby Lice (Nymphs) Look Like
When a nit hatches, it releases a nymph, which is essentially a miniature version of an adult louse. Nymphs are about the size of a pinhead, so they’re significantly harder to spot than adults. They’re the same shape and color, just smaller. A nymph takes about 9 to 12 days to mature into an egg-laying adult, so catching them early matters.
What Lice Bites Look Like on Skin
Head lice bites cause itching but rarely leave visible marks beyond small red bumps on the scalp. The itching is an allergic reaction to louse saliva and may not start until weeks after the initial infestation, which is why you can have lice for a while before noticing symptoms.
Body lice leave more noticeable marks. You’ll often see small areas of blood and crusting at bite sites, particularly where clothing seams press against skin: the waistband, bra line, collar, and upper thighs. Scratching these bites can break the skin and lead to secondary bacterial infections. If a body lice infestation lasts a long time, the skin in heavily bitten areas can thicken and darken, especially around the midsection. This long-term skin change is sometimes called Vagabond’s disease, and it appears as brownish discoloration with a leathery texture.
Pubic lice bites produce itching in the groin area, and they can leave a distinctive mark: pale blue spots at feeding sites. These bluish spots are unique to pubic lice and don’t occur with the other types. They can be harder to notice on darker skin tones.
How to Tell Lice Apart From Dandruff and Debris
The most common confusion is between nits and dandruff, and there’s a simple physical test. Try to flick the white speck off the hair. If it falls away easily, it’s dandruff or a bit of hair product residue. If it’s cemented to the hair shaft and resists your fingers, it’s likely a nit. Dandruff also sits on the scalp itself, while nits are attached to the hair strand just above the scalp surface.
Another helpful clue is pattern. Nits appear in an organized way, glued individually to hair shafts at a consistent distance from the scalp. Dandruff is scattered randomly. If you’re unsure, a fine-toothed lice comb run through wet hair is the most reliable detection method. Comb from the scalp outward over a white paper towel or cloth, and any live lice or nits will be easy to spot against the light background.
Where to Look for Each Type
For head lice, start behind the ears and at the nape of the neck. These are the warmest areas of the scalp, and lice prefer them. Part the hair in small sections under bright light, looking both for crawling adults and for nits glued to hair shafts near the roots.
For body lice, skip the skin and check clothing first. Look along the inner seams of shirts, underwear, and pants, particularly garments worn close to the body. The lice and their eggs live in fabric and only move to the skin to feed.
For pubic lice, examine coarse body hair in the pubic region, but also check the armpits, chest, and even eyebrows or eyelashes if itching extends to those areas. The adult “crabs” grip the base of hair shafts and can be easier to spot than head lice because they move more slowly.