One of the peak times for head lice infestations is when children have returned to school after the summer holidays – so be ready to debunk some common myths and misconceptions about this unlovely parasite...

 

 

Head lice is the second commonest communicable health problem among children after the common cold. Infestations are commonest in children aged four to 11 years, with the peak age for infestation at seven to eight years of age. There is little information on the current prevalence of head lice infestation.

“We don’t know and we have never known what the prevalence of head lice is,” says Ian Burgess, director of the Medical Entomology Centre. “All the studies over the decades have only ever shown what is known as a point prevalence – how many there were on that day in that place.”

“Despite the introduction of physically-acting products that should not be affected by resistance issues, the actual numbers of cases we find in schools have not dipped significantly overall, although you get ups and downs. “What we have found is that most children with lice have fewer, which makes them harder to detect. The refractory cases – where parents refuse to do anything for whatever reason – do not seem to change much and, of course, keep the system going.”

Treatment

NICE advises that treatment should start only if a live head louse is found using wet or dry detection combing.¹ If lice are suspected, then all household members need to be checked. There are many different treatments available that work in slightly different ways – so pharmacy staff need to be knowledgeable about how each product works, says Cathy Crossthwaite, Numark’s marketing co-ordinator.

“This category is important to community pharmacy as infestations can be a sensitive issue, with many people embarrassed that they or their children may be affected. Even if people are self-selecting products from the GSL category, they may still require advice as to whether they have chosen the best product for their situation.”

The range of treatments and methods can be overwhelming, especially for people buying a treatment for the first time, she says. According to NICE, there is limited evidence to support the effectiveness of each treatment option.¹

“No option is clearly superior or inferior to the others in terms of effectiveness... there are advantages and disadvantages for each method and no method can guarantee success,” it says. Customers should be advised that all treatments need more than one treatment session, it adds, and that treatment has the best chance of success if performed correctly and if all affected household members are treated the same day.

Pharmacy staff should stress that people need to check whether treatment was successful by detection combing on day two or three after completing a course of treatment, and again after an interval of seven days (day nine or day 10 after completing a course of treatment). It is also important to ensure that the head lice products recommended are suitable for groups such as babies under six months old, pregnant women, and people with asthma or allergies.

 

Treatment options

NICE recommends the following management options:

Dimeticone 4% lotion (Hedrin lotion)

This is a silicone-based physical insecticide that works by coating head lice and preventing them from eliminating water, causing them to die. The lotion does not kill eggs, so must be repeated after seven days to kill any lice that have hatched from eggs since the first application.

Dimeticone is left on the hair and scalp for eight hours (or overnight) and then washed out. It is suitable for all ages, those with skin conditions and those with asthma. It cannot be sold OTC for children under six months and has a good safety record.

Dimeticone 92% spray (NYDA)

This is a physical insecticide and is not suitable for children under two years of age.

Isopropyl myristate and cyclomethicone (Full Marks Solution)

This physical insecticide kills head lice by dissolving the wax coating on the louse exoskeleton, leading to uncontrollable dehydration and death. It is suitable for those with asthma but not suitable for children under two or people with skin conditions.

The solution should be applied twice, with seven days between applications. After being left in place for 10 minutes, the hair should be combed with a fine-toothed comb to remove lice and then washed using shampoo to remove the solution.

Malathion 0.5% aqueous liquid

This chemical insecticide has been used for many years to kill head lice. It is suitable for all ages and those with skin conditions but cannot be purchased OTC for children under six months. It should be applied twice, with seven days between applications.

The insecticide needs to be applied from the roots to the tips of the hair, left on the hair and scalp for 12 hours or overnight, and then washed out using shampoo. The disadvantage of this product is its unpleasant smell and there is now strong evidence that head lice are becoming increasingly resistant to chemical insecticides.

Wet combing

Wet combing (e.g. using the Bug Buster comb and method) is suitable for all ages, those with skin conditions and those with asthma. Treatment involves methodically combing wet hair with the fine-toothed comb to remove lice four times over two weeks. Wet combing should be continued until no full-grown lice have been seen for three consecutive sessions.

The advantage of this method is that no insecticides are used so resistance is not an issue, but the technique is time-consuming and labour intensive, which may be a drawback if several people are to be treated at the same time. Research has shown that bug busting is the most effective OTC treatment for head lice when compared to insecticides.²

Why treatment fails

Human error is the commonest reason why treatments fail, says Ian Burgess. Reasons for treatment failure include:

• The diagnosis of a head lice infestation may have been incorrect
• The customer may not have followed the treatment instructions correctly – not applied enough treatment, not applied it thoroughly enough, or not applied a second treatment
• If wet combing, the correct type of comb or combing technique might not have been used for a sufficient duration and for the recommended number of sessions 
• The lice may have been resistant to the chosen treatment
• The person treated may have picked up a new infestation immediately after the treatment finished
• Family members who are secretly harbouring lice may not have been treated.

How to manage treatment failure

• Advise the customer to repeat the same treatment or switch to a different treatment
• Advise that household members and close family and friends be assessed using detection combing to identify possible sources of reinfestation
• Whichever treatment strategy is chosen, ensure that all affected household contacts are treated again simultaneously. Other affected close contacts should also be treated to reduce the risk of reinfestation
• Stress the importance of checking that the treatment has worked by detection combing for up to 10 days after treatment.

Get yourself known

Joanna Ibarra, programme adviser for Community Hygiene Concern, a charity that promotes the Bug Busting solution, advises pharmacists to contact local schools that promote educational Bug Busting days in October, January and June. “Pharmacists should ask schools to give parents the message that they can get help from the pharmacy,” she says.

“Every term there will be new parents who will be taken by surprise at finding their children have a head lice infestation and will go to the pharmacy for advice and treatment. “This is a terribly time-consuming and annoying problem that many people have to cope with on top of the stress of daily life, so helpful advice will endear pharmacy in the eyes of the public.”