Head lice: causes and risk factors

While clothes and pubic lice have become rare, head lice still populate human hair, especially in children. Head lice infestation pediculosis cavities occurs again and again, especially in kindergartens and schools, whereby hygiene does not play a role and in this case it is advised to get appointment of lice doctors. The parasites don’t care if their hair is clean or dirty. That means: Even if you wash your hair every day, head lice can lodge in it.

The head lice especially like to romp around on the temples, behind the ears, in the neck and on the back of the head. Here the skin is very thin and has the optimal temperature for the little bloodsuckers. Usually, head lice infestation is limited to the hair on the head. If the infestation is severe, the small parasites can sometimes also be found on other hairy parts of the body – in the eyebrows, armpit hair or in the beard.

How do head lice feed and multiply

The head lice feed on human blood. To do this, they pierce the smallest blood vessels capillaries in the scalp every four to six hours and then suck up the escaping blood. The saliva that the animals release into the small wound prevents it from coagulating immediately.

The food available at all times allows the head lice to reproduce diligently: the females can produce 90 to 140 eggs during their four-week lifespan . They lay the eggs around 17 to 22 days after fertilization: they attach them to the hair near the scalp with a special secretion. This “glue” is insoluble in water, so that the eggs do not peel off during normal hair washing.

The eggs are oval, about 0.8 millimeters long and have a chitin shell. The larvae also called nymphs usually hatch from them seven to eight days after being laid . These develop into sexually capable adult head lice within nine to eleven days. It takes about three weeks from the freshly laid egg to the reproductive louse.