How do head lice form?

Head lice do not form; they hatch from eggs. Female lice lay eggs called nits on the hair shaft close to the scalp. The nits are laid at the base of the hair shaft and cemented to the hair with a glue-like substance. These eggs hatch into nymphs 7 to 10 days later. The nymphs mature into adult lice in about a week. Adult lice can live for 30 days on the scalp and lay up to 10 eggs each day.

Head lice are not caused by poor hygiene. Anyone can get head lice, regardless of their socioeconomic status or personal hygiene habits. Head lice are spread through head-to-head contact with someone who is infested with lice. They can also be spread through contact with clothing, hats, scarves, or other objects that have been infested with lice.