Eggs that still contain a louse embryo are brownish in color, while the empty egg shells are white to grey. As the hair grow approximately 1cm a month, eggs that are about 1cm from the scalp are more than likely to have already hatched or to contain a dead embryo.
There is no way to look at a nit with the naked eye and determine if it is dead or alive. And although some people claim it does, popping them does not prove that one way or the other either. They are just too small. The only proof is when they don't hatch 7-10 days later.
If nits are yellow, tan, or brown, it means the lice haven't hatched yet. If the nits are white or clear, the lice have hatched and just the egg remains. Lice eggs hatch within 1 to 2 weeks after they're laid.
Dead nits are often black in colour and are found well away from the scalp. Nits are laid on the hair shaft within 1cm of the scalp and take about 7-10 days to hatch into head lice. They will only hatch in a moist, warm environment such as the scalp.
Lifespan of Lice
The nits (eggs) hatch into lice in about 1 week. Nits (eggs) that are over ½ inch (1 cm) from the scalp are empty egg cases. They are very white in color. Off the scalp, nits (eggs) can't survive over 2 weeks.
If you spot nits, but do not see any lice, it is possible that they are hiding and scurrying from the light as you search the hair and scalp; they can move quite quickly! Focus your search to their preferred hideouts, behind the ears and at the nape of the neck.
Fresh eggs are a golden-brown colour and are plump and shiny before they hatch. Hatched or empty eggs are white and flat. As the hair grows the eggs are further down the hair shaft. It is important to look out for both brown nits and their white eggs.
Head lice are tiny, wingless insects that live in human hair and feed on blood in the scalp. Nits are the eggs of head lice. Brown-black nits are eggs that haven't hatched into lice yet. White nits are eggs that have already hatched.
Live lice eggs are small brown or tan coloured dots on hair shafts close to the scalp. These can be incredibly difficult to spot. Broken egg shells, or nits, are easier to spot. It's common for parents to mistake nits for dandruff.
The lice themselves take 7 to 11 days to hatch, so after that what is attached to the hair is the empty eggshell or the dead nit. These will stay attached to the hair and as the hair grows you will find them further and further down the hair shaft. They can stay there to the very end.
If a person cannot find any nymphs or adult lice in the scalp and the nits are more than a quarter of an inch from the scalp, these may be dead and from an old infestation.
If you do not comb out all the remaining nits, they will hatch and restart the cycle in 7-10 days from that point. That's why we recommend 3 treatments over a 12-day period of time.
Lice eggs (nits).
These look like tiny yellow, tan, or brown dots before they hatch. Lice lay nits on hair shafts close to the scalp, where the temperature is perfect for keeping warm until they hatch. Nits look a bit like dandruff, but aren't removed by brushing or shaking them off.
Use of a fine-toothed louse comb may facilitate identification of live lice. If crawling lice are not seen, finding nits attached firmly within ¼ inch of the base of hair shafts suggests, but does not confirm, the person is infested. Nits frequently are seen on hair behind the ears and near the back of the neck.
If you see nits and small moving lice, you've likely had lice for 1.5 to 2 weeks. This is because you aren't seeing a lot of adult lice but are still seeing tiny freshly hatched nymphs. If you find generations of head lice, meaning different sizes including nits, nymphs, and adult lice: 2 weeks or longer.
Nits often appear yellow or white although live nits sometimes appear to be the same color as the hair of the infested person. Nits are often confused with dandruff, scabs, or hair spray droplets. Head lice nits usually take about 8–9 days to hatch.
Eggs are white when they are first laid and turn brown before they hatch (Figure 2). Once they hatch, eggs are called nits. Eggs are glued to individual hair strands about 1/2-inch from the scalp. This glue is so strong the eggs cannot be as easily removed as dandruff and other hair debris.
There's no need to wash your child's bedding every day.
Sally's tip is to take a roller lint brush--the kind with tape--and run it thoroughly over the top half of your child's sheet. Her logic: The odds of a louse or nit falling off your child's hair and getting under the pillow and remaining alive is remote.
Therefore, because a nit must incubate under conditions equivalent to those found near the human scalp, it is very unlikely to hatch away from the head. In addition, if the egg were to hatch, the newly emerged nymph would die within several hours if it did not feed on human blood.
Nits take about 1 week to hatch (range 6 to 9 days). Viable eggs are usually located within 6 mm of the scalp. ) and become adults about 7 days after hatching. .
Since eggs do not need a host to survive, they will continue to live until a nymph hatches from it. A louse will ultimately die without a human host. However, it can still live for 1-2 days on a pillow or sheet.
Head lice sometimes go away on their own because there are not enough insects to maintain the infestation, or they may persist for an indefinite period without treatment. With proper treatment, the infestation usually goes away within about two weeks.