By Lice Clinics of America

You’ve probably heard the term “nit-picker.” It refers to people who pick nits out of someone’s hair. OK, so then what is a lice nit (or more correctly, a louse nit)? Nits are lice eggs that take about 8-9 days to hatch lice nymphs, which then grow into adult lice, which (if they are females) lay more nits.

A female head louse will lay about 4 eggs a day, gluing the nits to a single hair shaft about a quarter inch (~0.5 cm) off the scalp.

Nits can be either viable, or not. A viable egg will hatch a nymph, whereas a non-viable nit won’t hatch anything, either because it is dead, or the nymph has already hatched (leaving an empty shell still glued to the hair).

Because lice nits are so small (they look like tiny yellow, tan or brown specks), it’s hard to know with the naked eye whether one is viable or not.

Under a microscope, nits look plump and round. But if you pull one off a head, they usually look flat, with a little tail (which is the part of the hair the nit was attached to).

Besides being very small and hard to see, viable nits have a pretty robust shell. Because of this, many lice treatments (whether they use pesticides, essential oils or suffocation products) don’t have a high efficacy rate at killing the eggs. That’s why most lice shampoos and related products require follow-up treatments about a week later – to kill the lice that survived the original treatment when they were nits.

Treating head lice with heated air has proven to be a highly effective way of treating nits. AirAllé™, the professional lice device that dehydrates lice and nits, kills lice and 99.2 percent of the lice eggs in a single treatment. View a nit picture before and after an AirAllé treatment.

Learn about lice nit treatment.