Break the head lice life cycle

April 8, 2016

When head lice are detected, the infestation could be in any stage of the head lice life cycle. Head lice may have just laid some eggs or the eggs may have just hatched. In an infestation, a person could have thousands of eggs on their head.

An egg is laid on a hair shaft, no bigger than a pin-head. It is firmly attached to the hair shaft with proteinaceous biological glue1. This helps provide a protective environment for the developing louse. At this stage they are difficult to detect given their size and colouring, and often mistaken for dandruff or droplets of hairspray.

After an incubation period of 6 to 10 days, the louse hatches leaving the egg behind on the hair shaft. The insect is referred to as a nymph. The newly hatched nymph must feed on blood within about 45 minutes of hatching to survive. It will pass through two more nymph stages before maturing to its adult size which takes around ten days.

At full maturity the louse is typically the size of a sesame seed. Once mature, the lice will begin to mate. The female during her adult life can lay up to 128 eggs. The fully mature louse will die anywhere between 32 and 35 days after hatching.

As soon as an infestation is detected, a treatment should be administered to break the life cycle and to successfully eradicate the lice. Head lice are notoriously difficult to get rid of due to the nature of the head lice life cycle and the minuet size of the eggs. It is difficult to kill all the lice eggs on an infested head. Depending on their stage in the life cycle, some eggs will remain viable after the initial treatment and a few days later nymphs can emerge, perpetuating the cycle. As eggs can hatch every 6 to 7 days, it is necessary to repeat treatments on day 7 and 14, to break the head lice life cycle and kill any newly hatched head lice.

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