Lotions and Sprays for Head Lice

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There are a number of lotions and sprays available which usually work well to clear head lice. Different ones may be suitable for different people, depending on age and medical conditions. An alternative option is wet combing treatment.

Head lice can be treated either with chemical treatments (insecticides) or by wet combing treatment. This leaflet is about treatment with lotions and sprays, which are chemical treatments. See separate leaflet called Wet Combing Treatment for Head Lice for details about the alternative.

Treatment is needed only if you see one or more live lice. Empty eggshells (nits) do not always mean that you are infested with lice. Nits can stick to hair even when lice are gone (for example, after treatment that kills the lice).

There are a number of effective lotions and sprays available for treating head lice. Each is briefly described below. For more details of how to use each treatment, read the instructions that come with the packaging. Which one you choose to use may depend on:

  • Your personal preference.
  • What you have tried before (if appropriate).
  • Your age.
  • Whether you are pregnant or breast-feeding.
  • If you have medical conditions such as asthma or eczema.

Each treatment has a good chance of clearing head lice if applied or done correctly and if all affected people in the household are treated at the same time.

These insecticide treatments either work in a physical way or a chemical way. Most work in a physical way by covering the lice and smothering them. Those that act in a chemical way kill the lice by poisoning them.

Dimeticone 4% lotion

Dimeticone is a silicone-based product. Dimeticone 4% (trade name Hedrin®) has a good safety record and is widely used in cosmetics and toiletries. You should apply the lotion to dry hair. This needs to be done twice - seven days apart. Each application is left on for at least eight hours (overnight) and then washed off with shampoo and water.

Dimeticone is thought to kill lice by a physical process rather than by any chemical effect. It is thought to work by blocking the tubes used by the lice to breathe and by blocking the way the lice pass out water, which kills them. However, it is not thought to kill unhatched eggs. This is why two applications are needed, seven days apart. The second application makes sure that any lice that hatch from eggs which survived the first application will be killed before they are old enough to lay further eggs.

Dimeticone is suitable for all ages, those with skin conditions and those with asthma. It is suitable for women who are pregnant or breast-feeding. It is available on prescription. You can also buy dimeticone over-the-counter (although not for children younger than 6 months of age). Over the counter, it comes in other formulations, such as a spray and a gel.

Dimeticone 92% spray

Dimeticone 92% spray (trade name NYDA®) is stronger than the 4% lotion and is thought to be more effective. It seems to be better at destroying eggs as well as killing adult lice. However it should not be used if you are pregnant or breast-feeding. It also should not be used in children under the age of 2. It is available over-the-counter, and on prescription.

It should be applied to dry hair, and left for 30 minutes. After this, hair should be combed through with the comb provided to remove the lice. It is then left on for eight hours, before being washed off. Again, this should be repeated after seven days.

Isopropyl myristate and cyclomethicone solution

The trade name for this treatment is Full Marks®. It works in a similar way to dimeticone. You apply the solution to the scalp and leave in place for 10 minutes. The hair is then combed with a fine-toothed comb to remove lice. Then wash using shampoo to remove the solution. Treatment should then be repeated in seven days' time. The second application makes sure that any lice that hatch from eggs which survived the first application will be killed before they are old enough to lay further eggs.

This treatment is suitable for those with asthma. It is not suitable for children younger than 2 years of age or people with skin conditions. It is not suitable for pregnant or breast-feeding women. It is available on prescription and also to buy over-the-counter.

Malathion 0.5% liquid

Malathion is a chemical insecticide that has been used for many years to treat head lice. The malathion kills the lice. There are various brands but the one available on prescription is Derbac-M®. You can also buy malathion over-the-counter (although not for children younger than 6 months of age).

It is suitable for all ages and for those with skin conditions. It may be used in pregnancy but is only advised if you have tried wet combing and dimeticone 4% and they have not worked.

You should apply the lotion twice - seven days apart. Each application is left on for at least 12 hours (overnight) and then washed off with shampoo and water. The second application makes sure that any lice that hatch from eggs which survived the first application will be killed before they are old enough to lay further eggs.

Various other insecticides have been used in the past. For example, permethrin is no longer recommended for head lice because there are concerns that many lice are now resistant to it. Phenothrin and carbaryl are no longer available in the UK.

There are various other treatments that are said by some people to work. Such treatments include tea tree oil, quassia, other essential oils and herbal remedies. However, there is a lack of research studies to confirm that they work well in most cases. Therefore, until more research is done, these other methods cannot be recommended. There is also no evidence that any substance applied to the head to protect against catching lice is effective.

Only if they have head lice. All people who live in the same home and other close head-to-head contacts of the previous 4-6 weeks should be advised to look for lice. These people should only be treated if live head lice are found. They do not need 'in case' treatment. All people with head lice in the same house should be treated at the same time. This stops lice being passed around again.

Check that treatment was successful by detection combing 2-3 days after completing a course of treatment and again after a further seven days. Treatment has been successful if no lice are found at both sessions.

  • Only use an anti-lice treatment when you are sure that you have, or your child has, head lice. In other words only use these treatments when you have seen a live louse. Do not use them for an itchy scalp 'in case'. Do not use them to prevent head lice.
  • If head lice come back again (recur) after treatment, think about whether other family members and close friends have been checked and treated. If they have not been, this may be a reason for the problem. The treated person can get head lice back again from untreated family or friends. Also make sure you have completed the course correctly, ie used it for the correct amount of time and repeated as instructed.
  • After treatment and when the lice have gone, it may take 2-3 weeks for the itch to go fully.
  • Nits may remain after lice have been successfully killed with the lotion or spray used. Nits are empty eggshells and stick strongly to hair. They will eventually fall out. If you prefer, a fine-toothed 'nit comb' can remove them.
Original Author:
Dr Tim Kenny
Current Version:
Peer Reviewer:
Dr Laurence Knott
Document ID:
4509 (v42)
Last Checked:
31/08/2016
Next Review:
31/08/2019
The Information Standard - certified member
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