Head lice are annoying, but they're not dangerous and they don't spread disease. They're not a sign of poor hygiene — head lice need blood and they don't care whether it's from someone who's clean or dirty. It's best to treat head lice right away to prevent them from spreading.

Can you die off lice?

Body lice can carry potentially deadly bacteria, but head lice need a live host to keep feeding on blood, said Alejandra Perotti, a professor of invertebrate biology at the University of Reading in England, who has studied how lice and mites can help determine the cause of death.

How long can you live with lice?

The adult louse is about the size of a sesame seed, has 6 legs (each with claws), and is tan to grayish white in color. Females can lay up to 8 nits per day. Adult lice can live up to 30 days on a person's head. They must feed on blood several times a day to survive and will die within 1-2 days off of the host.