How do you get head lice and nits?

Itchy scalps, tickly heads - why do primary schools seem to be such a hotbed for head lice and nits? And where on EARTH do the cheeky little blighters come from in the first place?


Many children sail through nursery with not a nit or head louse in sight – and then, BOOM! The creepy crawly parasites put in an appearance when your little one gets to school.


So where do head lice come from? Ian Burgess is a medical entomologist based in Cambridge who says they’ve been around for thousands of years.

Nits and head lice are basically ANCIENT

Nits and head lice have lived on humans since we became – well, human, says Ian: “We evolved with it – or, it evolved with us.”

He adds that there’s the same genetic gap between the human louse and chimpanzee louse as between humans and chimpanzees themselves.

And, it seems, parents through the ages have battled the same problem of nits and head lice: archaeologists have found nit combs dating back to 1,500BC and discovered royal combs complete with head lice in them from Ancient Egypt ?

We should note here: nits and head lice are for humans specifically and have only ever lived on humans.


You don’t get them from your dog or cat, who have their own wondersome array of parasites (mainly fleas).

And in a nutshell – the way you get them is by having them passed on to you from someone else. And as long as there’s someone around with nits, there’s a chance someone else could catch them – as mum LadyTottington on our forum commented:

“[Nits] can be hard to get rid of. [My son] just kept being [re-infested] – the school was sending letters home and everything.

“It turned out that it was a girl with long hair (lovely hair!) whose mum just didn’t realise she had them. So she just kept on [infesting] the whole class?”

The good news is head lice can’t jump from one person to another. The bad news is primary school-aged children often play and work closely with friends, meaning the insects can crawl from one head straight onto the next.

How do nits and head lice get into your children’s hair?

Ian explains: “Closeness is simple – it’s physical contact. Out of all human beings, primary-aged children are the ones who have fewest inhibitions with being in contact with each other.

“The very young ones are still feeling their way, they don’t have many close contacts. But by the time they reach year 1 they are much more relaxed.”


This close contact risk of catching head lice increases through primary school until you get towards the end of years 5 or 6 and start secondary school aged 11 and up, says Ian.

Nits and head lice don’t disappear when primary school stops

But children aren’t out of the woods once they hit big school. “The biggest risk factor for those who are older is transmission from younger siblings,” he confirms.

And anyone who works with or lives with young children is susceptible too, as mum MayaJmum on our forum reveals: “I used to work at a nursery school, and the joys of it!

“If the kiddies were sick I would get sick… as was it when head lice did the rounds… “

If there are lots of lice it could just take a few seconds for them to move from one head to another, says Ian, if they are in the mood to move, that is.

“It’s the hair at the front and sides that is at risk because this is where humans have head to head contact.”

Once a louse has crawled onto a new head it won’t be long before adult females lay their eggs – this is what the nits are.

Eggs are fixed firmly onto a hair shaft close to the scalp and don’t easily fall off (even after the louse has hatched) which is why they can be easier to spot than a live louse.

Luckily, you only need to treat your child if you find live lice. Nits stick to the hair very strongly and can take weeks to fall out – long after the lice have hatched out and gone.

Treat the whole family if one of you gets head lice

Family GP, Dr Philippa Kaye, says it’s important to remember that everyone in the house will need to be checked – including adults – if one person get head lice, as, essentially, the way they’re passed on is from one head to another.

“You are looking for live lice, not just the nits,” she tells us. “The egg casings are difficult to distinguish from dandruff and also remain stuck to the hair for many weeks, until the hair has fallen out.”


Now, the good news is, today there are lots of products available, which you can get as a shampoo, spray or lotion, and which can be used on children from 2+.

Will head lice and nits ever disappear entirely?

“Not if I know human beings,” Ian tells us. “Most people are pretty incompetent at dealing with them in a variety of ways.

“Detection of them in the first place is something lots of people are not very good at, so the first hurdle is finding them.

“The second hurdle is dealing with them adequately – if at all.” Despite clear NHS guidance on how to effectively combat head lice, some parents choose not to bother, which is frustrating for families trying to deal with nits.

Though there’s no doubting, they are a nightmare to deal with. As mum KazzieM on our forum says: “The joys of head lice!

“A single louse can lay many eggs which can hatch after 3 days, it then takes around a week for those lice to mature enough to lay their own eggs. This is why checks should ideally be done weekly.” Perhaps a fair point.

As part of his research, Ian and his team go into local primary schools and any child found with a live louse is given a £10 voucher for head lice products – the ‘nit shampoos’ needed to beat the problem. Ian tells us that less than half of those are ever redeemed.

As parents, we are often horrified our child has caught head lice, and that doesn’t help the situation, Ian adds. “The problem with lice is that it gets people to engage their emotions before they engage their brain.”

If it’s any consolation for when (or if) your child gets nits, it’s worth remembering that head lice are extremely common – second only to the common cold among primary-school aged children, and have been around, as we’ve seen, for pretty much EVER.

So if you discover your child has them – treat them as best you can and they will go away.

And be thankful that, as well as doing plenty of combing, there are now lots of options out there to get rid of them effectively – unlike for those Ancient Egyptians…

Pics: Getty

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