You should only treat your child if you find live head lice, which confirms a live infestation. Don't treat "just in case". Head lice are tough. They can't be killed by washing with normal shampoo or normal combing. Because they reproduce so quickly, you've got to kill them before they spread to others. If your child has head lice, check everyone in the family. You'll need to treat everyone affected to get rid of them. You can treat head lice by wet-combing hair with a special comb (nitty-gritty) or by using medicated lotions or sprays (Hedrin) available over the counter at pharmacies.
The wet combing method involves removing the head lice by systematically combing the hair using a special fine-toothed comb. The comb's teeth should be spaced 0.2-0.3mm apart. Lice can be crushed or trapped between the teeth of nit combs with a tooth spacing of less than 0.19mm and remain unseen. You can buy a fine-toothed comb from your local pharmacy or you can order one online. Lotions or sprays don't need to be used for wet combing. However, to be effective, wet combing needs to be carried out regularly and thoroughly. The method you should use is described below.
How long it will take to comb your child's hair will depend on the type of hair they have and its length. For example, short, straight hair can be quickly prepared and can be fine-toothed combed in a few minutes. Longer, curlier hair will take longer to comb.
Lotion or sprays
Using a lotion or spray is an alternative method of treating head lice. However, to be effective they need to be used correctly. Your pharmacist will be able to recommend an over-the-counter lotion or spray and advise you about how to use it correctly. A lotion or spray should only be used if a living (moving) head louse is found. Crème rinses and shampoos aren't thought to be effective and therefore aren't recommended. Ensure you have enough lotion or spray to treat everyone in your family who's affected. Use enough to coat the scalp and the length of the hair during each application.
Follow the instructions that come with the lotion or spray when applying it. Depending on the product you're using, the length of time it will need to be left on the head may vary from 10 minutes to eight hours. The normal advice is to treat the hair and repeat the treatment after seven days. Some products also supply a comb for removing dead lice and eggs.
Some products may be capable of killing eggs as well as lice, although there's no certainty of this. Check for baby lice hatching from eggs three to five days after using a product and again 10-12 days afterwards. At least two applications of lotion are needed to kill lice over the hatching period because the lotions don't always kill louse eggs. If the lice appear unaffected by the product, or if the problem persists, seek advice from your school nurse, health visitor, pharmacist or GP.