Where are head lice most commonly found?

They are most commonly found on the scalp, behind the ears and near the neckline at the back of the neck. Head lice hold on to hair with hook-like claws found at the end of each of their six legs. Head lice are rarely found on the body, eyelashes, or eyebrows.

Head lice grip on to hair by their claws and rapidly move from hair to hair. They don't jump or fly but can quickly move from one person to another if in close proximity. By injecting saliva into an infected person's scalp they are able to suck blood which provides their nutrition. This can occur up to five times a day. A short time away from the scalp means the lice are unable to feed and therefore die.

Itching and irritation results from the louse feeding.

Lice lay eggs (nits) on the hair shaft close to the scalp. Here the warmth of the scalp will incubate them. The nits are cemented on to the hair and are carried away from the scalp as the hair grows. They hatch at around 8 days. The empty egg case then turns white and becomes more easily seen. The louse reaches full maturity at around 10 days after hatching. If mating occurs the female louse can lay 50-100 eggs at a rate of six per day.

In most infestations there are usually only a dozen or so lice at any one time, but there can be hundreds of eggs.