Head Lice Life Cycle

A head lice life cycle lasts around 35 days; that is the life cycle of an individual louse from the time the egg (nit) has been laid until they perish. This does not mean that a head lice infestation will only last thirty five days, quite the contrary, while one head lice (louse) has perished they leave behind a family of anywhere up to one hundred and fifty lice that have the potential to create more head lice. The life cycle continues until all head lice and nits have been completely removed from the scalp and hair.

Head lice are only transferred by direct human contact, they are NOT DANGEROUS, do not carry diseases and are not a sign of poor hygiene. This contact can come from hugs, sharing hair ties, brushes and caps. Head lice crawl exceptionally fast and have a firm grip on the hair once in contact, the transfer can happen in an instant. It only takes one louse to start the head lice life cycle.

Once head lice are in the hair they will start feeding immediately and the female louse will begin to lay eggs or as many of us call them - nits. The female louse can lay anywhere between fifty and one hundred and fifty nits which are generally laid about one centimetre from the scalp, commonly behind the ears and the back of the neck.

Seven to ten days later the eggs will hatch producing a nymph, leaving the empty nit shell in the very place it was laid. This egg will eventually disintegrate but this can take months, generally the shell would need to be physically removed during the combing stage of a head lice treatment.

A nymph is an adolescent louse which over the next twenty days will moult (shed) its shell in three stages. The moulting of the nymphs shell is part of its transformation into an adult louse.

Female lice pair with a male counterpart just hours into their adult life, preparing for reproduction and with little embryonic development from the female the eggs are laid.

Once the eggs hatch the head lice life cycle begins again.

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