What Does an Adult Head Louse Look Like?

Size Adults are roughly 2 to 3 mm long, about the size of a sesame seed. Females are usually a little larger than males. At that size you can see a louse with the naked eye, but it is easy to lose in thick or dark hair. A magnifying glass and good light help.

Colour Adult lice are usually tan to greyish-white. The CDC notes that on people with dark hair, the louse appears darker. A louse that has just fed can look reddish-brown, because the blood meal shows through its body. On blonde or light hair, a pale louse can be harder to pick out – see what lice look like on blonde hair and on brown or black hair.

Shape and Legs The body is flattened and elongated, with a small head, a narrower middle section and a wider abdomen. It has six legs, each ending in a claw adapted for gripping a single hair. Head lice have no wings. They can't fly or jump; they only crawl, which is why they spread mainly through head-to-head contact.

Movement Movement is often what gives a louse away. When you part the hair, lice tend to crawl away from the light, back towards the scalp. If you see something that moves, it is far more likely to be a louse than dandruff or debris, which stay put.

Head lice go through three stages: egg (nit), nymph and adult. These figures come from the CDC:

| Stage | What it looks like | Key facts | |-------|--------------------|-----------| | Nit (egg) | Tiny oval speck about 0.8 mm long, glued to one side of a hair, yellow to white | Hatches in about a week (6 to 9 days). Viable eggs are usually within about 6 mm of the scalp | | Nymph | A smaller version of the adult, about the size of a pinhead | Becomes an adult about 7 days after hatching | | Adult | Sesame-seed sized, six clawed legs, tan to greyish-white | Lives up to about 30 days on the head; females lay around six to eight eggs a day. Dies within 1 to 2 days off the head |

Finding a live nymph or adult is the best way to confirm head lice, according to the CDC. Finding only nits is less certain: nits more than about 6 mm from the scalp are almost always hatched or dead. See what a baby head louse looks like for nymphs, and live nits vs dead nits for eggs.

Adult lice stay close to the scalp, where it is warm and they can feed. They rarely wander to the ends of long hair. Focus on the roots, and start where nits are most often found: behind the ears and at the nape of the neck. Our guide to where to look for lice first walks through each area.

Finding a Louse With a Detection Comb Wet combing is the method the NHS recommends for finding and removing lice:

Wash the hair with ordinary shampoo and apply plenty of conditioner. Using a fine-toothed detection comb, comb from the roots to the ends in small sections, keeping the teeth against the scalp. Wipe the comb on white kitchen roll after each stroke and look for lice. Against white, a louse shows up as a small dark or tan body with legs. When you've combed the whole head, go through it a second time.

| Lookalike | What it looks like | How it differs from an adult louse | |-----------|-------------------|--------------------------------| | Dandruff or dry skin | White or grey flakes | Irregular, flat and loose. Doesn't have legs or move | | Hair spray or gel droplets | Hard, shiny beads on the hair | Clear or product-coloured, no legs, no movement | | Scabs or skin debris | Small brown or dark specks | Irregular shape, no legs, doesn't crawl | | Dirt, sand or fluff | Small dark particles | Loose and doesn't move on its own | | Other small insects | Different body shape, often with wings or long antennae | Head lice have a flattened body and clawed legs for gripping hair |

If you're not sure, comb the speck out and look at it on white kitchen roll under a magnifying glass. Our guide to tiny bugs in hair covers other insects you might find, and our AI head lice checker can give a quick screening result from a clear photo. Neither replaces finding a live louse with a comb.

Head lice are common in school-age children and are not a sign of poor hygiene. The CDC notes that they don't spread disease. The main problems are itching and the hassle of treatment.

UK guidance. The NHS says to treat lice as soon as you find them, check everyone you live with or have close contact with, and treat anyone who has lice on the same day. You can wet comb on days 1, 5, 9 and 13 and check again on day 17, or use a medicated lotion or spray from a pharmacy. The NHS does not recommend permethrin products, lice "repellents", electric combs or plant oil treatments. There's no need to keep a child off school.

US guidance. The CDC says children with head lice don't need to be sent home early from school. They can be treated at home and go back once treatment has started. Over-the-counter and prescription treatments are available; follow the pack instructions or ask a healthcare provider.

Wherever you are, check the pack for age limits and ask a pharmacist if you're unsure, for example for a baby or if you're pregnant or breastfeeding. Our treatment reviews compare the main products, and the NitNOT fine tooth comb review covers one widely used detection comb.

When to Get Help Speak to a pharmacist, GP or a professional head lice clinic if:

treatments haven't worked and you're still finding live lice the scalp looks infected from scratching, for example red, swollen or weeping skin you can't tell whether what you've found is a louse the hair is hard to comb properly at home

Use this answer as one piece of evidence, not the whole decision. If you want a quick second check, start with the AI head lice checker, then compare your result with the wider AI Detection hub so you can see where this question fits in the bigger picture.

If what you are seeing still overlaps with common lookalikes, compare it with what do head lice look like in hair and what do nits look like on hair shafts before moving to treatment on guesswork alone.

When the evidence remains mixed after a better photo or repeat check, move from uncertainty to confirmation. The most practical escalation routes are How to Choose a Head Lice Clinic Near You and the Head Lice Clinic Locations hub.

If active lice becomes likely, use the shop treatment reviews and the review of the NitNOT Fine Tooth Comb as decision support rather than treating every doubtful sign automatically.