Head Lice Facts

Chapter 3

In this segment, you will learn about the head lice lifecycle. Head lice go through three stages throughout their short lifetime of approximately 30-45 days. Lice begin as nits (or, head lice eggs) and will develop and hatch over the course of 10 days after being laid. When nits hatch, they become a nymph, tiny insects barely visible to the naked eye. Nymphs cannot lay eggs, as they have not yet sexually matured. After 10-12 days, a nymph is fully matured and becomes a louse, capable of laying eggs.

Did you know, a louse can lay up to 10 eggs per day? That is just about 100 eggs in a lifetime of 30 days, which of course, can be more if the louse lives closer to 45 days. Lice must feed on human blood every 4-6 hours or they become weak and eventually perish. That is why a louse will typically live no longer than 48 hours off of a human host.

Nits are laid close to the scalp for warmth during incubation. They are commonly found behind the ears and at the nape of the neck, but can be laid anywhere on the head. Nits found further than a ¼" from the scalp have likely already hatched, and it is just the shell that remains.