Head Lice Parent Information.

Head lice are tiny wingless insects that are grey-brown in colour. They are the size of a pinhead when they hatch and 2-4mm long (the size of a sesame seed) when fully grown.

They cannot fly, jump or swim, but spread by clambering from head to head. It takes about 30 seconds for a louse to transfer from one scalp to another.

Head lice feed by biting and sucking blood through the scalp. They take 6 to 14 days to become fully grown, after which they are capable of reproducing.

The female louse lays eggs in sacs (called nits), which are very small, dull in colour and well camouflaged. Nits are securely glued to hairs, where the warmth of the scalp will hatch them out in 7 to 10 days.

Empty sacs are white and shiny and may be found further along the hair shaft as the hair grows out.

Who is affected?

Anyone with hair can catch head lice, but children who have head-to-head contact, either at school or during play, are most commonly affected. Head lice can affect anyone, whatever the length or condition of their hair (whether it is dirty or clean).

Head lice affect only humans and cannot be passed on to or caught from animals.

How are they treated?

Head lice and nits can be killed using lotions, or physically removed using the wet combing method (see Treatment for more information). 

If you are worried about head lice or want more advice on how to treat them, consult your school nurse, health visitor, pharmacist or GP.

Last reviewed: 11/01/2010

Next review due: 11/01/2012

Head lice are difficult to remove because of their size, reinfestation rate, life cycle and their ability to develop immunity to insecticides.

Once an infestation is confirmed, the lice can be treated at home using either the wet combing method or medicated lotions (see below).

Neither method will protect against reinfection if head-to-head contact is made with someone with head lice at a later date.

Wet combing method

The wet combing ('bug busting') method involves physically removing lice using a nit comb, without using chemical treatments. This method can be helpful because head lice are growing increasingly resistant to the insecticides used to remove them.

However, success depends on adopting a painstaking approach of regular and thorough combing.

The best procedure is as follows:

• Wash the hair as normal using an ordinary shampoo.
• Apply conditioner liberally to wet hair (this causes the lice to lose their grip on the hair).
• Comb the hair through with a normal comb first, until the comb runs freely.
• With a fine-toothed nit comb, comb from the roots along the complete length of the hair. After each stroke, check the comb for lice and wipe it clean. Work methodically over the whole head for at least 30 minutes.
• Rinse the hair as normal.
• Repeat every three days for at least two weeks.

You can buy a 'Bug Buster' kit, which includes an illustrated guide and combs, from some pharmacies and by mail order from the Community Hygiene Concern website.

Only one kit is needed for a family, and it is reusable. You will need to repeat the sesssion every three days for at least two weeks to clear the lice. If the person catches more lice, the half-weekly sessions must continue.

Medicated lotion or rinse

Ask your pharmacist for an over-the-counter insecticide lotion or dimeticone (non-insecticide) lotion. Only use a lotion if you find a living (moving) head louse.

Apply the preparation according to the instructions. Remove the lice and eggs with a fine-toothed nit comb. Take care when applying treatment because the preparations are usually toxic.

The normal advice is to treat once and repeat seven days later:

• insecticide lotion should be left on for 12 hours or overnight and repeated after seven days, and
• dimeticone lotion should be left on for eight hours or overnight and repeated after seven days.

Make sure you have enough lotion to treat all those affected in your family.

The lotion may be capable of killing eggs as well as lice, but there is no certainty of this. Check for baby lice hatching out from eggs three to five days after you use it, and again at 10-12 days after.

No treatment is 100% effective.

Resistance

If the lice appear to be unaffected by the product (some lice may have developed resistance to a particular insecticide) or if the problem persists, take advice from your school nurse, health visitor, pharmacist or GP.

Caution

Always ask for advice before using medicated lotions on young babies (under six months), pregnant women or people with asthma or allergies, and always read the instructions carefully.

Pregnant women are advised to use either wet combing or dimeticone, which is licensed for use in pregnancy and breastfeeding.

http://www.nhs.uk/Conditions/Head-lice/Pages/Treatment.aspx