Head lice

Written by: 
Dr Roger Henderson

What are head lice?

Head lice (Pediculus capitis) are tiny greyish wingless insects that live by sucking bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. from the scalp of human beings. They cannot be caught from animals, and their eggs - which look like tiny white flecks - are known as nits. These are laid at the base of human hairs and are firmly glued in place by the insect using a sticky glue-like substance to prevent them from being dislodged.

Lice walk (they don't jump) from one head to another and so are commonly caught at school, where there is more likely to be close head-to-head contact between children. Although they can live for extended periods only in the hair, there is a chance that they may survive for a short time once they have left the body, so it makes sense to wash and dry items such as towels, clothing, bedding and soft toys (using heat) to avoid reinfestation or transmitting lice to others sharing your living space. It is thought that 5-10 per cent of schoolchildren are affected by head lice every year.

What symptoms do head lice cause?

Many people wrongly believe that head lice are in some way linked to dirty hair but in fact they can make themselves equally at home whether hair is clean or not. In the early stages there are usually no symptoms but after a few weeks they may cause itching of the scalp. Lice eggs (nits) are very small and well camouflaged, taking 7-10 days to hatch. It is the empty white egg sacs that are usually spotted, and may be found farther along the hair shafts as the hair grows out. Lice take 7-14 days to become fully grown and able to mate, when the female starts laying eggs again.

What is the best way of spotting nits or lice?

The most effective way by far to tell if you or someone else has lice is to use a special lice-detector comb, often called a 'nit comb' - a normal comb will not work since the teeth are too wide to catch any lice. The hair should be dampened, doused with conditioner and combed from the roots to the tips, wiping the comb onto a clean white sheet of tissue paper each time. If lice are found on the comb or paper, it is advisable to start treatment.

What is the best treatment?

Wet-combing, or 'bug-busting', methods do not use chemicals and involve thorough and methodical fine-combing of wet, conditioned hair every 2-3 days for at least 2 weeks using a fine-toothed nit comb.

Head lice can be extremely stubborn to clear and it may take weeks or even months of treatment before they are fully eradicated.

Insecticide lotions or creme rinses can also be used to treat live lice, and are usually applied once a week for 2 weeks. The preferred lotion treatment is changed regularly by doctors to prevent lice becoming resistantA microbe, such as a type of bacteria, that is able to resist the effects of antibiotics or other drugs. to the chemicals. Regular washing of clothing and bedding at a high temperature may help, but need not be excessive.

It's advisable for any close contacts who are also infested, both inside and outside the family, to be treated at the same time.