As a mother of four school-age children, Jennifer Barton has become a master of making sure uniforms are clean, that homework gets done on time and that everyone leaves for school each day with a healthy packed lunch.

But every year, especially at this time, she struggles with head lice.

Over the past decade her children Diana, 14, Liv, 11, Stella, nine, and Ada, seven, have had at least one or two infestations a year between them.

This hasn’t just affected them – it’s also been a problem for Jennifer and her husband Will, 40, who works in finance.

The first sign, she says, is the ‘dreaded itching on the scalp’.

‘Even if only one of our kids has lice, we treat the whole family with dimeticone-based head lice treatment [a silicone-like compound which smothers the bugs] until the lice have been eradicated because they spread so easily.’

She also checks her children’s hair every day. ‘We learned years ago that this is the only way to stay on top of things,’ she says, wearily.

Head lice affect thousands of UK households every year and while cases dropped during the pandemic, they are now soaring – if the market for head lice products is a guide (Superdrug reported that sales of treatment spray surged by 121 per cent compared with a year ago).

And the problem is never more acute than at this time of year, when children are once again in close contact with each other in classrooms.

Most parents dread the email that typically comes weeks into the school term announcing another outbreak.

But although parents are often embarrassed to admit their child has head lice, they are ‘very common and nothing to be ashamed about’, says Dr Sharon Wong, a consultant dermatologist and spokesperson for the British Skin Foundation. ‘They are nothing to do with personal hygiene.’

Lice are actually one of our oldest parasites, adapting to changes in human behaviour. As David Reed, associate provost at the University of Florida, and an expert on the genetics of mammals and their parasites, recently told National Geographic, this is apparent from the size of their claws, which match the diameter of human hairs.

Their ability to adapt is reflected in the fact that when we started wearing clothes, lice developed into two forms, body and head lice.

‘People often refer to them as nits but those are actually the empty shells of head lice eggs,’ explains Dr Wong.

Driving the rise in cases, suggested an earlier Dutch study in 2016, is the trend for youngsters putting their heads together and taking selfies.

This is something Dr Wong says is ‘possible’ as head-to-head contact is the most common way to spread head lice. Sharing personal items such as hats or hairbrushes is less likely, according to research from James Cook University in Australia in 2010.

Similarly with bedding: the NHS advises that ‘washing clothing and bedding on a hot wash is unnecessary, as it’s unlikely to prevent the spread of head lice’.

The popularity of long hair may also play a role. A survey earlier this year by the University of Valencia in Spain suggests having short hair halves the risk of getting head lice.

However, as Dr Wong, explains: ‘People with all hair lengths can get head lice, although they may be easier to see and eradicate in short hair.’

Despite their tiny size (an adult louse is about the size of a sesame seed), they can spread with terrifying ease. ‘About 30 seconds of contact is all that’s needed and that is easily done in households and schools,’ says Dr Wong.

This is why they can easily become ubiquitous among children in playgroups, schools, clubs – and get passed on during playdates and sleepovers.

Jennifer, 42, has lost count of the number of times she’s caught head lice from her children. Her first infestation was when her eldest Diana was in nursery.

‘I was stressed the first time my eldest got nits because it felt overwhelming,’ she recalls.

‘I’d heard about it, but I wasn’t prepared for how prevalent they still tend to be, even as kids get older and into secondary school.’

During one bout of head lice, Jennifer was pregnant with her youngest child.

After being alerted to the possibility by a fellow mum, she immediately checked her own daughter – and found a couple of lice.

She was worried about using chemical treatments so enlisted her husband’s help in treating the problem with conditioner and wet combing – where you comb wet hair using a fine-toothed nit comb and a thick conditioner, which effectively traps the lice and helps remove them and their eggs.

‘Thankfully we’d caught them super early so there were only a couple of lice and we managed to get them off,’ says Jennifer.

Although some parents swear by the old wives’ tale remedy of combing with vinegar, Dr Wong says home cures are not as effective as chemical treatments. The best way to get rid of head lice, she explains, is to use dimeticone-containing products. These ‘are derived from silicone oil and work by smothering the lice and suffocating them.’

Essentially lice consume more water or fluid than they actually need, which they excrete through their respiratory system. Dimeticone blocks the respiratory tubes, preventing the lice from releasing excess fluid, ‘which then kills them’, says Dr Wong.

And because it is not an insecticide, it’s not harsh on the scalp.

Dr Wong also suggests using the wet comb method as a belt-and-braces approach, as dimeticone normally needs two applications, a week apart.

In the UK there are two insecticides, permethrin and malathion, which work by attacking the insect’s nervous system.

However, increasingly head lice have become resistant to both. Back in the 1980s, permethrin had a near 100 per cent clear-up rate, but a study published in the BMJ in 2007 found it cleared only 13 per cent of cases. It’s a similar story for malathion.

The rise in insecticide-resistant ‘super’ lice ‘is a global problem’, explains Ian Burgess, a medical entomologist at Insect Research and Development, Cambridge, a centre which advises the NHS on parasites and tests new products.

‘Malathion was introduced in 1991 and by 1993 we found there was resistance to it,’ he says. ‘In the clinical studies using permethrin in the late 1990s and 2000s, we were getting at best 30 per cent of people cured.’

Ian Burgess says there are new treatments on the horizon though he cannot reveal details: ‘I am just given them to test, I don’t know what’s in them.

‘But even if they are better, we need to keep a watch and make sure lice don’t get used to them because we have even seen the odd case of lice becoming tolerant to dimeticone.’

Prevention may be better than cure: but counterintuitively, shaving your head won’t work – ‘unless you do it every day,’ says Ian Burgess.

‘We did a study in Bangladesh where, in summer months, the kids shave their heads because it’s so hot. In one place, twin girls with long hair both had lice and one cut her hair to a bald pate.

‘The girls shared a bed and within two days the one who’d shaved her head had stubble coming through and lice again.’

For the Barton family, head lice prevention is a military operation with the parents regularly checking for new signs of infestations.

‘My husband is amazing at comb-through removal. We also treat at the first sight of a louse and repeat after a few days, with daily comb-throughs in between,’ says Jennifer.

‘Hair stays in ponytails, brushes are disinfected, sheets, pillows and clothes all washed. You have to stay on top of it. Our nine-year-old recently got them at a sleepover and it’s taken several weeks to get rid of them.’

Dr Wong agrees that such vigilance is key – along with treating all family members simultaneously regardless of whether they’ve been infected.

And most importantly, she adds, ‘have patience’.