Lice 101: Get to Know the Enemy

Get to your enemy. Learn what happens with lice on the 1st day of exposure to the 20th and beyond.
Nits no lice

1st Day of Exposure to Lice

A fertile female louse goes onto a new host over 95% from hair to hair contact. She lays 3-5 nits right away and has 5-6 blood meals per day. Most likely she won’t survive transferring to a new host but she left behind 3-20 hard to detect nits that will hatch.

→Person is mildly contagious for about 24 hours from initial exposure to lice. After that there are no bugs, only nits. They won’t be contagious for 2-3 weeks.

Days 7-10

Nits hatch 7-10 days from when they are laid. Every time a mommy louse lays her nits there’s always one male bug and the rest are females. A nit is mostly ½”-1” from the scalp on a hair shaft and feels like a grain of sand stuck to the hair. When a louse is first hatched it’s called a nymph. The nymphs will rarely leave their host’s head until mature & fertilized.

→At this point here maybe tiny bugs and nits. The person is not contagious yet.

Days 10-20

Every few days these nymphs will shed their outer shell or exoskeleton 3 times before they become full-grown adults. The male fertilizes the female one time and she’s fertile for life. A PERSON IS ONLY CONTAGIOUS WITH AN ADULT FEMALE LOUSE. The female lays her 1st nits 24 hours after being fertilized. She can lay 3-5 eggs twice a day for the rest of her life. She can lie up to 150 nits in her lifetime.

→Day 14 a person can have a contagious case of lice and by the end of 20 days have adult and baby lice and up to 100 nits. May begin to feel itchy.


When a female louse lays her nits there’s always one male nit laid. Every 7-10 days is a new generation of lice. 10% of her nits may never hatch. The louse dies having lived 30 days since being laid as a nit.

→Infestations beyond 30 days often have all stages of live lice and hundreds of nits. This person continues to be very contagious until all live lice are defeated.
Lice will not go away on their own. The infestation must be treated safely and
properly to defeat the life cycle of a louse.

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