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How to find head lice

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Adult head lice crawl from one person's hair to another's hair when heads are held close together. Check hair thoroughly with a lice comb at least once a month to detect them and avoid further spread.


Adult head lice crawl from one person's hair to another's hair when heads are held close together. Check hair thoroughly with a lice comb at least once a month to detect them and avoid further spread.

Children are more exposed to infection than adults.


Lice cannot jump but they creep from hair strand to hair strand. Once lice come away from the hair, it is unlikely that they will establish themselves on a new head. They quickly become weak and survive for only 1-2 days away from a head. 

Both adults and children can get head lice, but they are most common among primary school children. Anyone can get lice, regardless of their hair type. Lice survive in hair that is washed often or seldom.

Children who are newly infected and adults with lice often lack symptoms such as itching and may unwittingly be a source of infection. If people with head lice in the same contact circle are not treated simultaneously, the risk of re-infection is great.


An itchy scalp is a common sign of head lice. Louse saliva contains substances which may cause itching when they enter the skin. However, not everyone with lice experiences itching or it can take time for it to start. Another symptom of lice is sores and scalp infections caused by scratched louse bites. 

kjemming hodelus
FHI - Anne Lene Solbakken

Use a lice comb and good lighting. Carefully comb damp or dry hair with a fine-toothed comb. We recommend wetting hair because this inhibits the louse’s movement and they will not be able to crawl from the uncombed hair into the already combed sections of the hair to hide.

Lay a white towel over the shoulders when combing wet hair and check the towel and comb for lice and eggs. Lice are small and a magnifying glass can be useful. Wipe the comb on paper. Lice will dry within a few minutes, and you will see them move.

Some people prefer to check for lice in dry hair. Lice move in dry hair and they may therefore be easier to spot, at least if there are many. Whoever is being combed should bend over a big white sheet and comb from the scalp and down towards the sheet.

Head lice are usually found in the nape of the neck, especially behind the ears, and up to the crown, but they can be found elsewhere on the head too. Most will only have a few lice (1-10), so a thorough check of the head is important to detect them.

Combing can also find lice eggs. They stick so well to the hair strand that the hair often breaks during combing with the egg still attached. Finding eggs alone is not a sure sign of an ongoing lice infection as they may have hatched or died. Live lice should be detected for a certain diagnosis. The egg's location on the hair shaft may help to determine the time of infection. Eggs are laid mainly near the scalp and hair grows about a centimetre per month.

You can find more information in the article What do head lice look like?

Perform a thorough lice check immediately if you hear about lice in your contact network, or otherwise suspect infection. The whole family should be checked. It is the parents' responsibility to examine their children for head lice.

To prevent infection, all parents should check their children at the start of school term and after holidays abroad if the children have been in contact with local residents. Studies have shown that the incidence of head lice in many countries is far higher than in Norway. A good rule is to use a lice comb on the children at least once a month, preferably every week.

You can find more information in the article How to treat head lice.

At school and childcare centres

If head lice are detected in children in childcare centres or school, it is not necessary to send them home. The child has probably had them for a long time, so a few hours make little difference. The child could wear a headscarf or other headgear to prevent infecting others.

When the child comes home, the first part of any treatment should be carried out the same evening. The child can go to child care or school as normal. Inform the childcare centre / school and contact circle that your child has head lice, so they can also check for lice and avoid reinfection.

The school/childcare centre should inform other parents or guardians that lice have been detected within the school grade/department.

Related litterature

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:

Head lice prevalence among households in Norway: importance of spatial variables and individual and household characteristics

Head Lice in Norwegian Households: Actions Taken, Costs and Knowledge

Socioeconomic status, family background and other key factors influence the management of head lice in Norway

Head lice predictors and infestation dynamics among primary school children in Norway

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