The time it takes for lice eggs to hatch is determined by many factors, including the temperature of the scalp and the location of the infested area. The temperature is probably the most important factor, since warmer temperatures are conducive to the development of lice. Thicker hair, on the other hand, can help the lice develop and hatch more quickly.
Adult lice don’t lay their eggs directly on the scalp, but instead deposit their eggs in nits on the hair shaft. In past studies, the time it takes for nits to hatch has ranged up to 14 days. However, these previous studies used body lice that were strapped to an arm or ankle. More recent studies use head lice raised in laboratory incubators, which are more stable than the human scalp.
Adult female lice lay three to eight eggs a day, so an infestation can grow quickly. They need bloodmeals several times a day to survive. Although head lice cannot fly, they can survive for up to two weeks on a person’s head. Afterward, they will die if they lack food and a warm environment.
Adult lice are smaller than a sesame seed, and can be difficult to detect in the hair. The nymphs are just a few millimeters long, and they feed on the scalp for up to a week. The eggs are very hard to detect, as they are white and oval. You may mistake them for dandruff or scabs, which are similar in size and shape.