Head lice and nits: how to get rid of them

Dealing with head lice - and the children they take hold of - ranks among the toughest tasks many parents and carers have to tackle.

And it is becoming more difficult. Many of the chemical treatments people have relied on for years are not as effective as they used to be, which means head lice can be harder to kill.

It is still possible to clear lice from your children - but you will probably need a good dose of patience and persistence.

Remind me, what are head lice? And nits?

Head lice are tiny insects with six legs that live only in the hair on a person’s head - and they are most often found among primary school-aged children.

They have been alongside humans throughout millions of years of our evolution.

Lice thrive in hair, but they regularly head down to the scalp up to half a dozen times a day to feed on blood.

Their claws are shaped perfectly for gripping and moving along hair shafts. However, although they are quick and agile in hair, they do not cope well away from it - off the head they are awkward, poorly coordinated, and they die quickly.

The word ‘nits’ refers to head lice eggs. They are often the first clue that a child has an infestation. With a single louse laying more than 100 eggs during its roughly month-long life, there can be many nits.

Can they spread diseases?

No. Head lice are irritating and their bites can trigger skin reactions. But Australian health authorities do not regard head lice as a health risk. There is no evidence head lice transmit pathogens that cause disease.

In fact, for children with head lice, the stigma associated with an infestation can be more harmful than any direct physical health effects.

Why do my children always pick up lice?

From childcare through to primary school, it is very likely your child will have head lice at least once. One Australian study reported that infestation levels in Australian classrooms ranged from no cases at all to 72 percent of children affected.

Girls are more likely to carry head lice than boys. Having long hair makes it easier for lice to transfer.

Head lice cannot jump or fly; they spread through direct head-to-head contact.

They arrive home with your children because children spend time close together - hugging, playing, or clustering around books or screens. Any contact where heads touch can allow an infestation to pass from one child to another.

Rules vary a little between states, but in New South Wales and Queensland children do not need to be kept off school solely because they have head lice.

How can I keep my home free of head lice?

A spotless house will not stop head lice. They are not bothered by how clean your sheets and towels are, or how often you vacuum carpets and rugs.

There may be some chance of lice moving via shared pillows, but even then the risk is small.

When you discover lice in a child’s hair, there is no need to change that child’s bedding or anyone else’s. Research-based guidance from NSW Health states that "bed linen, hats, clothing and furniture do not harbour or transmit lice or nits and that there is no benefit in washing them as a treatment option".

I've used nit solution. Why isn't it working?

Your local pharmacy stocks many different head lice treatments. Products are assessed by Australia’s Therapeutic Goods Administration to ensure they are safe and effective.

Even so, most of these treatments are insecticides that kill lice on contact but may not kill the eggs.

Another issue is incomplete use. If you do not follow the directions on the label and finish the treatment exactly as instructed, some lice may survive.

On top of this, head lice appear to be developing resistance to the chemicals commonly used against them, which is making it harder to fully clear infestations.

So how can you get rid of them?

Do not expect a miracle cure, but Australian health authorities generally recommend the ‘conditioner and comb’ (or ‘wet comb’) approach. This technique removes lice physically, without needing chemical treatments.

There are three key steps:

1. Immobilise the lice by working hair conditioner through the child’s damp hair, then leave it in place for about 20 minutes.
2. Comb through the hair methodically with a fine-toothed "lice comb". Wipe the conditioner and lice onto paper towels or tissues. You will mainly catch adult lice at this stage - but that is fine, because the eggs are handled later.
3. Do the process twice in total, with roughly a week between sessions, to interrupt the head lice life cycle.

Doing it again after a week gives any remaining eggs time to hatch. Although it sounds counter-intuitive, once hatched the young lice are easier to remove than the eggs. The key is to remove them before they mature and start laying a new set of eggs, which would keep the infestation going.

Children are much more likely to have head lice, but in practice anyone in the household can host a louse or two. You may not need to treat everyone, but "grown ups" should watch for lice as well.

Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of Sydney

This article is republished from The Conversation under a Creative Commons licence. Read the original article.