Head lice are common. They can usually be cleared with treatment.
This leaflet is part of our series on head lice
|Checking for head lice|
|Lotions and sprays for head lice|
|Wet combing treatment for head lice|
What are head lice and nits?
Image via Wikimedia Commons
- Head lice are tiny grey/brown insects. They are about the size of a sesame seed (the seeds on burger buns). Head lice cling to hairs but stay close to the scalp which they feed off. Head lice lay eggs which hatch after 7 to 10 days. It takes about 7 to 10 days for a newly hatched louse to grow into an adult and start to lay eggs.
- Nits are the empty yellow-white eggshells which are left when the lice hatch. Nits look like dandruff but stick strongly to hair. Unlike dandruff, you cannot easily brush out nits.
Who gets head lice?
Head lice are common in children but can affect anyone of any age. They are not a sign of dirty hair or poor hygiene. Close hair-to-hair contact is usually needed to pass lice on. Head lice cannot jump or fly but walk from one head to another. They soon die when away from hair, and do not live in clothes, bedding, etc. Most head lice infections are caught from family or close friends who are not aware that they have head lice.
What are the problems with head lice?
Many people with head lice do not have any symptoms. An itchy scalp occurs in some cases. This is due to an allergy to the lice, not due to their biting. It often takes about three months for an itch to develop after you are infested with lice. Therefore, you may not notice that you have head lice for a while and you may have passed them on to others by the time you are aware of them. Head lice and nits do not wash off with normal shampoo. Head lice do not usually cause any other medical problems. The number of lice that may be on one person can vary greatly. There may be just a few in some, in other cases there are more than 100. Very rarely in very severe cases there may be over 1,000. Typically in the UK, there are around 30 lice present on each affected person's head.
How can you tell if you have head lice?
Head lice are difficult to find just by looking in the hair. If you suspect that you (or your child) have head lice, it is best to comb through the hair with a detection comb. Some people advise that you do this to children's hair regularly, about once a week. This may not always be necessary but can be helpful if people you are in contact with have head lice, or if it is a recurring problem.
Detection combing: wet hair method
This will take 5-15 minutes to check each head, depending on hair length and thickness. It is also used as a treatment for head lice - see later.
- Wash the hair in the normal way with ordinary shampoo.
- Rinse out the shampoo and put on lots of ordinary conditioner.
- Comb the hair with a normal comb to get rid of tangles.
- When the hair is untangled switch to a