What are head lice?

Head lice are the most common parasitosis in children, frequently affecting those aged four to 11 years.1 Small parasitic insects, they live and thrive on the human scalp, laying up to ten eggs each day. These eggs stick to the hair shaft for about eight days before hatching and leaving behind empty egg case or 'nit'. Nine to 12 days later the matured lice are greyishbrown in colour and can measure up to 3.5 mm long.

Who suffers from head lice?

Anyone can catch head lice but traditionally the peak infection age is 7-8 years,3,4 probably because they can only be caught by direct head-to-head contact, making the classroom an ideal transmission ground (it is a myth that head lice can jump, fly or swim). However, an increasing amount of research into incidence has shown that head lice tend to be more common in girls than boys,3,4 lice tend to go undetected for longer in those with longer or fairer hair5 and those from lower socio-economic groups do tend to suffer more.5 Whether the latter is down to more confined living space or less compliance with treatment applications remains up for debate. One thing that is for sure is the old wives tale that lice like dirty hair is an absolute myth. They love clean hair, but are unfortunately just not washed
away by normal shampooing, brushing or normal combing.

Detection is the key

Treatment should only begin if a living, moving louse is detected so it is vital that you are well informed on the subject and able to help advise customers regarding detection. The first sign of an infection is usually itching, which is caused by a hypersensitivity reaction to lice saliva, but not everyone feels this, and there can be a time lapse before the itching is felt. To this end, the only way to tell for sure is to encourage the customer to have a really good look. In an ideal world the hair should be checked while wet or damp and it usually takes a good 20 minutes to do a thorough look. To facilitate this procedure, which let's face it, is unpleasant for all, you could suggest they treat their wet hair with conditioner as this should help any head lice to lose their grip. Then the hair should be combed in small sections from root to tip with a special lice comb to find immobilized head lice or nymphs.

Treatment advice

With 79% of people6 now looking to the pharmacy for a treatment, there has never been a better time to update your knowledge of the latest head lice treatment offerings. Traditionally these have centred around four chemical insecticides that are licensed as head lice treatments - malathion, phenothrin, permethrin and carbaryl. However, fuelled by scare stories of asthma attacks and allergic reactions triggered by strong smelling chemicals and theories that the lice have become immune to some of these chemicals, 61% of parents6 say they are now looking for a non-toxic treatment that is pesticide-free. There are a new generation of pediculicides which are nontoxic (i.e. do not contain insecticide) and can effectively eradicate an infection with just one application; killing head lice and nymphs within minutes7 and eggs within 8 hours. There main component is dimeticone, an ingredient endorsed by the Public Health Medicine Environmental Group as one of the most favourable treatment options for head lice infection.8.

How do they work?

Dimeticone is able to penetrate deeply into the spiracles of lice and nymphs, as well as into the pores of head louse eggs. Once there it interrupts the flow of oxygen, and causes asphyxiation of the lice at all three stages of their development. Within 60 seconds of application, lice show no vital signs, and - unlike tests with other head lice treatments where the treated lice recovered - this is irreversible. Crucially, because of this physical mode of action, resistance cannot develop and if used as directed, only one application is needed to completely eradicate the head lice infection.

What about safety?

These products are free from toxic ingredients and are well tolerated - in fact children as young as two are able to use it. There is little or no absorption of dimeticone and so adverse effects commonly associated with insecticidal treatments, such as skin irritation and scalp itching, appear to be rare.1

Simple strategies for successful selling6

  • Know your stuff - treatment should only be recommended if a live louse has been detected. Consider nominating a member of staff to be responsible for advising patients
  • Bear in mind that head lice can be resistant against conventional products based on insecticides.
  • Link sell - although dimeticone should get rid of an infection with just one application, everyone in the family who has signs of a live louse should be treated at the same time so more than one pack may be required.
  • Similarly, head lice are hard to prevent so encourage early detection next time by recommending a nit comb. Finally, if itching continues to be a problem an antihistamine may help.

This article was submitted by Pohl Boskamp Limited.


1) Clark C. Pharmaceutical Journal 2007; 279: 185-188

2) Headlice and worm treatment sales. IRI InfoScan 52 weeks to 27 Dec 2008.

3) Downs Am et al. Epidemiology and Infection 1999; 122:471-7

4) Speare R et al. International Journal of Dermatology 1999;38:285-90

5) Willems. S et al. The importance of socio-economic status and individual characteristics on the prevalence of head lice in schoolchildren. Eur J Dermatol 2005; 15 (5): 387-92

6) MyChild online survey

7) Oliveira FA et al. J Eur Acad Dermatol Venereol 2007;21(10):1325-9

8) Public Health Medicine Environmental Group (PHMEG). Head Lice: Evidence-Based Guidelines Based On The Stafford Report 2008 Update

9) Quote obtained from Ian Burgess, Insect Research and Development, interviewed in 2005