Quick Answer
Head lice can only survive on a human scalp.
- On the head: up to 30 days
- Off the head: 24–48 hours
- On furniture or bedding: they die quickly and do not infest homes
How Long Do Lice Live?
Head lice (Pediculus capitis) are blood-feeding insects. They spend their entire lives on the human scalp and feed exclusively on blood. The egg is firmly attached to a hair close to the scalp, where the climate is sufficiently warm for the baby louse inside the egg to develop. The development takes approximately seven days and then a new little head louse is ready to crawl out of the egg. This timing is one of the main reasons over-the-counter lice treatments often fail, especially when eggs are missed. During the first stage of the head louse life cycle, in which it is not yet fully grown, the head louse is called a nymph. During the nymph stage, the head louse casts off skin every three days and grows rapidly. The louse more than doubles its size in just 10 days .
According to Kids Health
While head lice are frustrating to deal with, lice aren’t dangerous. They don’t spread disease, although their bites can make a child’s scalp itchy and irritated, and scratching can lead to infection. (Source: KidsHealth)
Before we go into the life cycle of head lice, it is important to know how long they live for. The average louse lives for about 30 days. It takes 7-10 days for a nit (lice egg) to hatch and another 7-10 days for them to mature and lay eggs.
The Three Stages of Lice: (Egg, Nymph, Adult Louse).
There are three main stages in the life of a louse. First comes the head lice egg (nit), then there is a nymph which is a baby, and then comes the adult, also known as a louse. Check out this funny video that explores the experience of having head lice and being a head louse.
The Life Cycle
Day 1: The nit is laid on the hair shaft. At first, it is extremely small.
Days 3-6: The nit is slowly enlarging and turning into a tan color.
Day 7: The nit now hatches into a nymph.
Days 8-9: The first moult occurs. (A moult is when the eggs sheds.) As the nymph ingests blood, it turns darker.
Days 10-11: The second moult occurs.
Days 12-14: The third moult occurs.
Day 15-17: The louse is now a mature adult.
Day 28-32: The lice completes its cycle and dies.
When the lice are adults, they mate. For the rest of the life of a female lice, it lays from 6 to 10 eggs per day.
Published: August 9, 2019
Still battling head lice?
Finished the article and still looking for answers? DIY treatments often fail. Our certified technicians provide guaranteed results in the comfort of your home.
Get Lice-Free Today
