Live Nits vs Dead Nits: How to Tell the Difference

Nits are head lice eggs. Female lice glue them to individual hairs close to the scalp, where it is warm enough for them to develop. The CDC describes them as tiny ovals about 0.8 mm long, usually yellow to white, and says they take about a week to hatch (6 to 9 days). A live nit still contains a developing louse. A dead nit is either an empty shell left after hatching or an egg that never developed.

Distance from the scalp is the most useful clue. The CDC says viable eggs are usually found within about 6 mm (a quarter of an inch) of the scalp. Nits found only further than 6 mm from the scalp point to a previous infestation rather than an active one, according to the CDC. Empty shells often look white, clear or dull yellow and can look flattened or open at one end. Eggs that have not hatched look fuller. Colour alone is not proof. The NHS describes nits as brown or white, so a brown nit is not automatically alive and a white one is not automatically dead. Nits never move. If something crawls, it is a louse, not a nit.

Because hair keeps growing, a nit carried far down the hair shaft was laid weeks ago. Shells stay glued in place long after the louse has hatched, which is why people often find nits after the lice themselves have gone.

A live nit is a small, fuller-looking oval glued at an angle to one side of the hair, close to the root. It is usually yellow to white, though the NHS notes nits can also look brown. It is firmly stuck and will not slide off when you brush, shake or blow on the hair.

Live nits are most often found where the scalp is warmest, especially behind the ears and at the nape of the neck. If you find several nits within 6 mm of the scalp, the CDC says that strongly suggests an active infestation, and it is worth doing a careful comb check for live lice straight away.

Dead nits come in two forms. Hatched shells are empty and often look white, clear or dull yellow. Eggs that died before hatching can be hard to tell apart from live ones by eye, which is why distance from the scalp matters more than colour. Neither kind can hatch, and neither can spread lice to anyone else.

Dead nits stay glued to the hair. The glue does not break down when the egg hatches or dies, so a shell can stay attached until it is combed out or the hair grows out or is cut. That is why a firm grip on the hair does not tell you a nit is alive.

If the only nits you can find are well away from the scalp and you cannot find any live lice, the most likely explanation is an old infestation that has already been treated or has run its course.

The NHS says the only way to be sure someone has head lice is to find a live louse. So the most useful check is a wet comb check for lice, not just a close look at the nits.

Check in daylight or under a bright lamp, with a white tissue or towel nearby. Wash the hair with ordinary shampoo and apply lots of conditioner. Any conditioner will do. Comb the whole head from the roots to the ends with a fine-toothed detection comb, section by section. You can buy detection combs online or from pharmacies. Wipe the comb on the tissue after each stroke and look for lice and eggs. When you find a nit, note how far from the scalp it was. Within about 6 mm suggests it may be a live egg. Further down suggests an old shell. When you have finished, comb through all the hair a second time.

The NHS says combing usually takes about 10 minutes for short hair and 20 to 30 minutes for long, frizzy or curly hair.

If you find live lice, treat. If you find only nits far from the scalp and no live lice, you do not need to treat, but it is sensible to check again over the next couple of weeks.

Lice and nits can be removed by wet combing. The NHS recommends wet combing on days 1, 5, 9 and 13 to catch any newly hatched lice, then checking again on day 17 that the hair is clear. That schedule works because eggs take about a week to hatch, so repeat sessions catch young lice before they are old enough to lay eggs.

If wet combing has not worked or is not suitable, the NHS says you can try a medicated lotion or spray from a pharmacy, supermarket or online. These kill head lice in all types of hair, and some come with a comb to remove dead lice and eggs. Some treatments need to be repeated after a week to kill any newly hatched lice. Check the pack to make sure it is suitable for you or your child and follow the instructions. If lotions or sprays do not work, speak to a pharmacist about other treatments.

The NHS does not recommend permethrin products, head lice "repellents", electric combs, or plant oil treatments such as tea tree, eucalyptus or lavender oil, because they are unlikely to work. The NHS also says not to use medicated lotions or sprays to prevent head lice, because they can irritate the scalp. If you have found nits but no live lice, comb and recheck rather than reaching for a lotion.

Dead shells do not need treatment. You can comb them out with a detection comb or nit comb, slide them off the hair with your fingers, or leave them to grow out.

Head lice are very common in young children and their families. They are not caused by dirty hair and spread through head-to-head contact.

Check everyone you live with or have close contact with, and start treating anyone who has head lice on the same day. There is no need to keep your child off school or nursery because of head lice. You do not need to wash laundry on a hot wash. Adult lice die within 1 to 2 days without a blood meal, according to the CDC, so they rarely survive long on bedding, hats or brushes.

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.