Head lice advice

Pharmacies and Health Care Professionals

Managing Head Lice

This information provided here is to refresh your knowledge about head lice management, provide useful resources and help you to make considered treatment recommendations when necessary.

We are the part of the pharmacy community that is on the treatment ‘front-line’. As such, we have an extremely important role to play in ensuring the correct advice reaches parents at the time when they need it most. So it is important that we are up to date with current evidence and best practice when we give advice and make recommendations.
Graham Phillips , Manor Pharmacy, Group Community Pharmacist
Head lice can be the cause of a great deal of frustration, upset and embarrassment for some parents and the pharmacy is often their first point of call for advice.
Ian Burgess, Director of the Medical Entomology Centre

As a pharmacist, you are a concerned parent’s first port of call for information, advice and treatment. But did you know that recent clinical trials have shown many traditional treatments have now become ineffective in dealing with head lice? So what are the key things you need to go over with a parent, a simple and memorable CHECK, TREAT, COMPLETE slogan was devised to help manage this condition, so the training has been split into these clear sections to help you.


This section tells you all there is to know about head lice and their impact, as well as explaining the important role of parents in managing this condition, including how and when they should be checking

A heads up on head lice – what are parents checking for?

  • Head lice (Pediculus capitis) are small, six legged wingless insects
  • They live on, or very close to, the scalp and don’t wander far along the hair shaft unless stimulated to move to a new head
  • A head louse’s mouth is like a very small needle, feeding from blood on the head
  • They spread through moderately prolonged head-to-head contact
  • They have a maximum lifespan of a month
  • They range from the size of a full stop to that of a sesame seed depending on their age – adult lice are just 3 to 4 millimetres long
  • At about 10 days old a female louse will start to lay eggs after being fertilised by a male louse – she will deposit between 50 and 150 eggs during her lifetime

It is important to note that nits are not the same thing as lice:

  1. Lice are the insects that move around the head. When it first hatches, a young louse (known as a nymph) is transparent but after its first blood meal, it will darken to a greyish brown colour
  2. Louse eggs are translucent which makes them hard to spot – they will be close to the scalp, difficult to see and even harder to remove with a comb
  3. Nits are the empty eggshells which remain glued to the hair shafts after the nymphs have emerged

The Impact of head lice

  • Anyone can get head lice, although they are most common amongst children aged 4 to 11 due to the greater levels of physical contact with peers
  • The best known symptom of head lice is the itching, which can lead to a loss of concentration and sleep, but this is not necessarily a reliable indicator as many people may not itch when they have head lice
  • Not treating them can lead to a loss of self esteem and confidence, and a general feeling of being unwell
  • Parents should be advised to try not to make too much of head lice – they are unpleasant but they rarely do any serious harm
  • Unsupported, the problem can cause parents and children a great deal of unwarranted anxiety and distress

Actual size of head louse
Advice You Can Pass Onto Parents – How to Check for Head Lice

  • A diagnosis of head lice infection cannot be made with certainty unless a living, moving louse is found – no matter how many nits are present, how many reported cases there are in school or how bad the itch is
  • If somebody has nits it doesn’t necessarily mean they have head lice – when you have got rid of all the lice, the nits will remain stuck to the hair until they grow out or they are combed out
  • Parents should check their children’s hair regularly, ideally once a week – a good way for parents to remember this is ONCE A WEEK, TAKE A PEEK
  • Remember, the presence of head lice will not always cause people to itch straight away, it can take over a month before this symptom develops
  • It is best to check for head lice using a detection comb made for the purpose, ideally white so they can be easily seen and with teeth no more than 0.3mm apart in order to trap head lice – research has found detection combing was nearly four times more effective than visual inspection for finding live lice
  • Combing through the hair using a conditioner may make the process more comfortable
  • Good lighting is important and so is comfort
  • Checking for head lice shouldn’t be considered a big deal, it is just a normal part of a family’s personal hygiene routine like brushing teeth or washing hair


This section provides you with information on the different treatment options available, as well as advice on effective application of treatments.
Treatment options for head lice
There are FOUR principle types of head lice treatment:

  • Pesticide treatments
  • Non-pesticide treatments
  • Wet combing with conditioner
  • Alternative treatments

Resistance to pesticide agents
There is now strong evidence that the head lice population already has, and continues to, develop resistance to a number of chemical agents, particularly Permethrin. In part, this is a result of inappropriate and overuse of these agents over a long period.
Effective treatment
When advising a parent or carer on which treatment is best for their child, the following points should be taken into consideration:

  • The customer’s recent use of chemical treatments and the issue of resistance with (pesticide) products
  • Any contraindications including asthma, skin conditions and allergies
  • The age of the child concerned as treatments are not licensed for those under 6 months

Pesticide Treatments
The pesticide treatments available, Malathion and Permethrin, work by poisoning the lice. There is evidence that levels of resistance to these treatments are rising.

Kills Lice

The Hedrin Range is PESTICIDE FREE

Non Pesticide Treatments
Non-pesticide lotions work in a different way from conventional pesticide treatments. By coating the outside of the lice, they disrupt their ability to manage water causing them to die. This physical mode of action means there is theoretically no chance for the lice to build up a resistance. There are two main active ingredient options currently in use, Dimeticone and Isopropyl Myristate. Based on clinical evidence, dimeticone is considered the most effective treatment of this nature and, in a recent study, was shown to be significantly more effective at eradicating lice than the pesticide alternative, Malathion.

Kills Lice

Hedrin and Hedrin 15 both contain DIMETICONE

The current evidence suggests that dimeticone is an effective agent, with lice eradication rates of 97% in a recent study.

  • Dimeticone provides a promising treatment option as its mode of action is one that is likely to avoid resistance issues
  • An overview published in the Drug and Therapeutics Bulletin concluded that on current evidence dimeticone should be seen as a useful alternative to products containing conventional pesticides

Based on the evidence currently available, I would recommend dimeticone as the first choice treatment option for head lice.
Ian Burgess, Director of the Medical Entomology Centre and advisor to the authors of the Stafford Report
Wet Combing with Conditioner
Some parents prefer to avoid any chemical treatments. In these instances, parents may wish to use a non-chemical approach, the most established of which is wet combing with conditioner.
Alternative Remedies
Parental concerns over the use of chemical preparations to treat head lice are common and a number of products based on alternative approaches are currently on the market. Unfortunately many of the alternative products available lack an evidence base or product license on which to assess effectiveness. In addition, the safety of some alternative methods is unknown and there is the risk that safety problems could arise.
Application of the Treatment

  • Treatment should only be applied if a living, moving louse has been found – never ‘just in case’.
  • Follow the manufacturer’s instructions and ensure the treatment is left on for the recommended time
  • When applying treatment, cover the full length of the hair if specified in the treatment instructions
  • Keep the lotion out of the eyes and off the face – don’t use a hair dryer and keep away from flames, stoves, cigarettes and other sources of heat


This section highlights the importance of repeating the head lice checking process once treatment has been applied, as well as what can be done if the problem won’t go away

Most treatments require them to be repeated seven days after the first application to kill any nymphs which have hatched since the first treatment was applied. The checking process should be repeated a couple of days after treatment to ensure that all the head lice have been killed.

Treatment Failure or Re-infection?
If the problem won’t go away, the following points should be kept in mind to avoid inappropriate use of head lice treatments, particularly when considering a possible treatment failure:

  • Was there in fact a true infection before application?
  • Is there in fact a current active infection now?
  • Has a second application been used (if specified in the pack instructions)? Are the detected lice simply those that have hatched after a first application? If this is the case any lice found should be young nymphs less than 3 millimetres long
  • Did the first head lice treatment fail? If it did then why? Possible reasons might include not using enough lotion, not applying it properly or problems with resistance if it was a pesticide treatment
  • Is it more likely that the first infection was cleared but re-infection has occurred? Any lice found are likely to be young adults, approximately 3 to 4 millimetres in size

It is also worth noting that some parents will seek treatment for perceived cases of head lice infection, which are not actually current infections but due to factors such as:

  • Itching scalp due to other skin problems such as eczema or impetigo
  • Other conditions, such as dandruff, mistaken for head lice
  • Psychogenic itch on hearing of other cases in the school
  • Treated infection but with nits still being found
  • Treated infection but with itch persisting
  • For parents experiencing repeat infections, recommend a head lice protection product which is supported with clinical evidence

Summary Reminder

When Disusing Head Lice with Parent or Carer:


  • Parents should check their child’s hair once a week
  • Use a proper detection comb – with teeth no more than 0.3mm apart to trap head lice, and white in colour so they can easily be seen
  • If find live lice, remind them they should come and consult a pharmacist for treatment advice
  • If head lice are spotted, take a close look at all the family, including yourself, and ask close family and friends to check as well


  • Only treat if live lice are identified
  • Use a clinically proven treatment, ideally with a physical mode of action to which lice are very unlikely to build up resistance (such as Dimeticone which is in Hedrin formulations)
  • Leave the treatment on for the recommended time for maximum effect – leaving it on for longer will not make it more effective


  • Check that all head lice have gone within 2-3 days of the final application to complete the treatment
  • If the pack instructions specify that a second application is required, repeat the treatment for a second time seven days after the first to kill any lice that may hatch from eggs during that time
  • Continue to check for head lice on a regular, weekly basis

Hedrin products are backed by some of the largest clinical studies ever conducted on head lice:

1,2-Octanediol, a Novel Surfactant, for Treating Head Louse Infestation: Identification of Activity, Formulation, and Randomised, Controlled Trials


Randomised, Controlled, Assessor Blind Trial Comparing 4% Dimeticone Lotion with 0.5% Malathion Liquid for Head Louse Infestation


Dimeticone 4% liquid gel found to kill all lice and eggs with a single 15 minute application


Treatment of head louse infestation with 4% dimeticone lotion: randomised controlled equivalence trial


The mode of action of dimeticone 4% lotion against head lice, Pediculus capitis