How to treat head lice
Head lice can be combated with delousing agents, by combing or by shaving the hair. Regular hair washing does not kill lice or eggs.
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Only individuals with lice should be treated because there is always a small risk of unwanted effects. Preparations for treatment of head lice are divided into two categories: medicines and medical devices. For all delousing agents, it is important to read the package insert carefully. If others in your family or contact circle have lice, they must be treated simultaneously to prevent re-infection. Check the hair weekly for three weeks after the last treatment.
Of lice products classified as medical devices, there are products with the following groups of active substances alone or in combination:
- Dimethicone (Linicin 15 min solution, NYDA and Hedrin)
- Plant oils
Dimethicone is a silicone composition that physically kills lice. Dimethicone products are documented to have good effects and are recommended ahead of plant oils which are less well documented.
In Norway, one medicine is available that contains permethrin (Nix shampoo). In recent years there have been reports from many countries of a large degree of resistance among headlice to this product.
None of the agents kill all the eggs, and the treatment must be repeated after 8-10 days.
For all medicines, there should be scientific evidence both for efficacy and possible unwanted effects. Medical equipment must be CE-marked to be sold in Norway. One of the requirements for CE marking is that the manufacturer must have clinical documentation to prove that the equipment has the effects claimed should not have any unwanted effects other than those stated.
A lice comb can be used to combat lice. Comb systematically and thoroughly every day or every other day for 12-14 days. The hair should be wet, preferably with conditioner to aid combing. Place a towel over the shoulders to catch any lice or eggs that fall down. Wash the towel and comb at 60 ºC, or freeze for at least four hours to kill lice and eggs. Check the hair weekly for three weeks after the last treatment. Read more about combing.
Combing dry hair makes the hair and comb static and young lice may be thrown from the comb back into the hair. Larger lice move more quickly in dry than wet hair and may climb into the recently combed hair sections or creep up from the shoulders if they fell off the comb during combing. It is therefore wise to have a towel over the shoulders so that any lice can be spotted and removed.
There is also a special hot air apparatus that can be used for combing, where lice dry out during treatment. This apparatus is not intended for home use.
Lice cannot survive on hair shorter than 0.5 cm. Shaving is a good treatment option, especially for young children. Please note that the lice will crawl among clipped hair after shaving. Some lice will also attempt to cling on to stubble. Use a lice comb to remove them.
It is possible for lice to spread via combs and brushes and these should be washed or frozen if there are lice in the household. Freeze combs and brushes to -20 ºC for at least four hours or wash them at 60 ºC.
It is not necessary to wash clothes, furniture or the house itself if somebody has headlice.
After lice treatment, wash bed linen to remove any old lice and their excrement.
An information letter is available in several languages which provides information and advice on infection and treatment of head lice:
In 2008 the Norwegian Institute of Public Health conducted two investigations regarding head lice in households of Norwegian school children. Some of the information above is taken from the four articles that were published: