Daily Mail Good Health section
By Caroline Scott
Clara Nunes’s heart sinks when she sees her three young children scratching their heads. She knows that head lice are, yet again, spreading through school like wildfire.
Over the past ten years the problem has become so widespread that head lice are a fact of life for many parents of primary school-aged children.
It’s now estimated more than a third (37 per cent) of all four to 11 year-olds will get them at least once a year, compared to just 1.5 per cent in 1977.
She is not alone. As the school year starts and parents prepare for the inevitable cycle of treating and retreating their children, some experts say products are often backed by poor evidence.
Furthermore, the most effective cure is vigorous combing with basic conditioner.
Head lice spread particularly rapidly among primary school-aged youngsters because they play and work closely enough together for their heads to touch, thus transferring the lice.
Because they breed so quickly — with an adult female head louse laying six to eight eggs a day — head lice are very difficult to eradicate.
Symptoms include constant itching, while in some cases an allergic reaction to the bite can lead to dermatitis and infections.
‘However, 53 per cent of children don’t scratch immediately, so by the time your child starts itching they’ve probably had lice for weeks or even months,’ says Dr Andrea Franks, consultant
There is no surprise, then, that the head lice industry, worth £33.5 million in the UK, is booming. Chemists’ shelves groan with ‘herbal’ shampoos and sprays, although no studies show that they work.
Other products contain insecticides such as Permethrin (Lyclear creme rinse) and Malathion (Derbac M liquid). These are all neurotoxins which act by irreversibly immobilising lice.
Newer to the market is the silicone-based ingredient Dimeticone (found in Hedrin, Hedrin Once and Nyda) which is said to kill lice and eggs by coating them and smothering them. All are available on NHS prescription. But the problem is that head lice are extremely adaptive and have eventually developed resistance to almost every product, which may explain the huge rise in cases.
In the Seventies, using Malathion to combat an infestation of head lice was more than 90 per cent likely to beat the problem.
But a study involving ten schools in Bath and Bristol in 1999 reported a 64 per cent failure rate for Malathion and a 87 per cent failure rate for Permethrin.
Research in 2006 involving Welsh school children suggested that 80 per cent of lice in that area were resistant to both Permethrin.
Because Dimeticone works by smothering the lice to kill them rather than poisoning them, it’s claimed the bugs are unlikely to become resistant to it.
A study published in the British Medical Journal in 2005 suggested a 65-70 per cent success rate. However. some experts question the validity of research into headlice products.
Professor Robert Vander Stichele, a Belgian GP, reviewed 28 studies of head lice treatments for a paper published in the British Medical Journal in 1995, and found much of the research deeply flawed.
He says his has been the only independent investigation in 15 years, claiming that research reflects the fact that it’s funded by drug companies.
‘Few entomologists with an interest in head lice control are completely independent,’ he claims.
‘It means there is a huge risk of bias.
‘Parents will go on buying the same lotion, hoping for a different result,’ he says, adding: ‘It’s an ideal market to sell expensive products which don’t quite work. All these products will kill some lice, but none kill all lice and eggs. After a couple of weeks, new lice hatch and you’re back where you started.’
In Australia last year, the advertising regulator for health products upheld complaints over an advert for Hedrin lotion which included the claim: ‘Kill rate 97 per cent clinically proven.’
The regulator was ‘by no means satisfied the study could support either the ‘kill rate’ or the claim that this kill rate was ‘clinically proven.’
The regulator also pointed out that several other studies suggested a significantly lower success rate for Dimeticone, Hedrin’s active ingredient. (In the UK TV campaign, the slogan is ‘Hedrin Once could kill head lice and their eggs’).
Meanwhile, there is also concern about the regulation of such products, suggests Dr Jose Figueroa, deputy director of public health for City and Hackney Primary Care Trust.
He says: ‘Some treatments are considered “liquid medical devices” which means there is far less regulation than there should be and studies don’t stand up to scrutiny, yet they should be as rigorous as those in any other area of medicine.’
One old-fashioned, yet apparently effective alternative is combing out the lice using normal conditioner on wet hair and a special fine-toothed comb.
A community scheme using this approach was pioneered on Teesside in the Seventies by the father of Sir Liam Donaldson, the former chief medical officer. It halved the level of infestation.
Mentored by Dr Donaldson, Joanna Ibarra, a mother of two set up the charity Community Hygiene Concern and developed the Bug Buster kit (four specially designed combs and a rigorous set of instructions) 30 years ago when she and her own children were constantly infested.
In the only long-term trial to compare the results of treating head lice with an insecticide product with those of wet combing, scientists from the London School of Tropical Medicine found that regular Bug Busting was four times more effective than chemical treatments.
The study observed 133 children over a year, and found wet combing to be 57 per cent effective compared with 13 per cent for Malathion. Wet combing is also recommended by the Department of Health’s NHS choices website.
However, while the technique is cheap (the kit costs £6.10) it is also time-consuming, needing around 15 minutes to thoroughly comb each head — and effective only if instructions are followed closely.
Wet combing must be repeated four times, leaving four days between sessions.
Indeed a report by the Public Health Medicine Environmental Group three years ago ruled out Bug Busting as an effective method of lice control since the skill level needed ‘does not exist amongst the general public’.
Some health authorities have since abandoned their Bug Busting campaigns in favour of Dimeticone-based treatments — to the consternation of Dr Franks.
‘We know that regularly combing conditioner through wet hair is the cheapest and most effective way of keeping on top of the problem,’ she says.
Caroline Wheeler, marketing director for Hedrin says: ‘The support package for Hedrin Once has come from an extensive programme of work both in the laboratory (in-vitro) and clinical studies.
‘Competitors have been keen to challenge our advertising claims but, having conducted a thorough review of the data file, the ASA ruled against a competitor challenge earlier this year.’