Head Lice are tiny insects that live in human hair.
They are particularly common in children.
Head lice are whitish to grey-brown in colour, and smaller than the size of a pinhead when first hatched. When fully grown they are about the size of a sesame seed.
They can’t fly, jump or swim and are spread by head-to-head contact, climbing from the hair of an infected person to the hair of someone else.
A head lice infestation isn’t the result of dirty hair or poor hygiene. All types of hair can be affected, regardless of its length and condition.
Head lice only affect humans and can’t be passed on to animals or be caught from them.
Head lice often cause a person’s scalp to itch. Itching isn’t caused by lice biting the scalp but by an allergy to the lice.
However, not everyone is allergic to head lice, so you or your child may not notice a head lice infestation.
Even if someone with head lice is allergic to them, itching can take up to three months to develop.
In some cases, a rash may appear on the back of the neck. This is caused by a reaction to lice droppings.
Life Cycle of head lice
A female head louse lays eggs by cementing them to hairs (often close to the root), where they are kept warm by the scalp. The eggs are pinhead-size and difficult to see.
After seven to 10 days, the baby lice hatch and empty eggshells remain glued in place. These remains are known as nits. Nits are white and become more noticeable as the hair grows and carries them away from the scalp.
Head lice feed by biting the scalp and feeding on blood. They take nine to ten days to become fully grown. Head lice normally only crawl from head to head when they are adults or nearly mature juveniles.
A female head louse may start to lay eggs from nine days after she is hatched. Therefore, to break the cycle and stop them spreading they need to be removed within nine days of hatching.
How to spot head lice
Head lice can be difficult to see, even when the head is closely inspected
Unhatched eggs or nits (empty eggshells) alone are not enough to diagnose an active head lice infestation. This is because it can be difficult to distinguish between eggs and nits that are dead or alive. Nits also usually remain glued to hairs long after successful treatment.
To confirm an active head lice infestation, a louse must be found through a reliable, accurate method, such as detection combing.
Detection combing is the best way of finding head lice. It involves using a special fine –toothed head lice comb with a tooth spacing of 0.2 – 0.3mm to comb through the hair. The comb can trap even the smallest lice. It works better on wet hair but can also be used on dry hair.
Treating head lice
Head lice can usually be effectively treated with lotions or sprays designed to kill head lice, or by wet combing, using a specially designed head lice comb (see above).
Wet combing can be used without lotions or sprays, but it needs to be done regularly and can take a long time to do thoroughly.
Lotions or sprays can be used as an alternative. However, to be totally effective they need to be applied correctly and thoroughly. Your pharmacist will be able to recommend an over-the-counter lotion or spray and give you advice about how to use it correctly.
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:
- Wash the hair using ordinary shampoo and apply plenty of conditioner, before using a wide-toothed comb to straighten and untangle the hair.
- Once the comb moves freely through the hair without dragging, switch to the louse detection comb. Make sure the teeth of the comb slot into the hair at the roots, with the bevel-edge of the teeth lightly touching the scalp.
- Draw the comb down to the ends of the hair with every stroke, and check the comb for lice.
- Remove lice by wiping or rinsing the comb.
- Work methodically through the hair, section by section, so that the whole head is combed through.
- Rinse out conditioner and repeat the combing procedure.
- Repeat the procedure on days three, six, nine, twelve and fifteen so that you clear young lice as they hatch, before they have time to reach maturity and lay eggs.
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.
Lotions 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 are not thought to be effective and therefore are not recommended.
Ensure you have enough lotion or spray to treat everyone in your family who is 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 are 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 is 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 G.P.
Always read the instructions on the pack or leaflet that comes with a head lice treatment, particularly in relation to the following groups.
- Young babies (under six months old)
- Pregnant women.
- People with asthma or allergies.
If you are still unsure, seek advice from a healthcare professional before using the product.
It is recommended that pregnant women use either wet combing or 4% dimeticone lotion, which is licensed for use during pregnancy and breastfeeding.
Afro (frizzy) hair or hair that is tightly curled can make treating a head lice infestation particularly difficult.
There is no evidence that keeping your child’s hair short, or plaiting or braiding it, will make it easier to treat.
Afro hair should be treated in a similar way to straight hair. Methodically combing small sections of hair at a time with a lice comb, and/or using a lotions or spray, will usually prove effective.
Head lice and clothing
Healthy head lice don’t deliberately transfer onto clothing, bedding or soft toys.
Their life span is about three weeks and when they fall from the head they are dying and unable to breed.
Hot washing of fumigation is not necessary to control head lice.
Promptly dispose of any lice that fall from the head on to clothing or bedding.
Head lice on combs
Inspect brushes and combs that are used during treatment and remove any lice before the next stroke.
Head lice will die after a day or two if they are unable to feed on human blood.
Be aware that the head lice can be flicked from dry hair during vigorous combing. If they land on someone they will try to climb up to their head.