head lice and nits

the facts

Head lice are a social pest and rarely pose a threat to health
Head lice only live on human heads
Head lice can live in clean or dirty hair
Head lice are transferred mainly by direct head-to-head contact; rarely by brushes, combs, ribbons, hats etc.
Head lice do not carry disease, but bacterial infections can occur from scratching the scalp
Head lice treatments often don’t kill 100% of the nits (eggs)
Successful treatment does not protect the person from getting infected again with more head lice

the most common reasons for treatment failure

Not following the manufacturer’s instructions
The resistance of head lice to the chemical used
Not repeating the treatment in 7-10 days (to kill head lice that have hatched from eggs that weren’t killed in the first treatment)
Getting head lice from an untreated individual

Head lice are tiny grey/brown insects. They are about the size of a sesame seed. Head lice cling to hairs, but stay close to the scalp which they feed off. Head lice lay eggs which hatch after 7-10 days. It takes about 10 days for a newly hatched louse to grow to an adult and start to lay eggs.

Nits are the empty white egg shells which are left when the lice hatch. Nits look like dandruff, but stick strongly to hair. Unlike dandruff, you cannot easily brush out nits. They are usually attached about 2.5 cms (1”) above the hair root. That is why short hair discourages head lice as the nits don’t like to be anchored too near the scalp.

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.

Most children with head lice have no symptoms. An itchy scalp occurs in some cases. This is due to an allergy to the lice, not due to them biting. Head lice and nits do not wash off with normal shampoo. Head lice do not cause any other medical problems. In many cases the head is not 'crawling with lice'. Commonly, there are less than 12 lice present.

If you or your child has an itchy scalp, and is found to have head lice this is usually a sign of a prolonged infestation, over 3 months, as it takes this long to develop the allergy leading to itchiness.

how to check for head lice – detection combing

Head lice are difficult to find just by looking in the hair. If you suspect that you or your child has head lice it is best to do 'detection combing'. This requires a special fine tooth comb.

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 detection comb. This is a special fine-toothed comb. The teeth of normal combs are too far apart. Some pharmacies stock detection combs.
Slot the teeth of the comb into the hair at the roots so it is touching the scalp.
Draw the detection comb through to the tips of the hair.
Make sure that all parts of the hair are combed by working around the head.
Check the comb for lice after each stroke. A magnifying glass may help.
If you see any lice, clean the comb by wiping it on a tissue or rinse it before the next stroke.
After the whole head has been combed, rinse out the conditioner.
It may take quite a while to do detection combing properly, depending on how thick and long your child’s hair is.

What if I find nits but no live lice?
Treatment is needed only if you see one or more live lice. Nits (empty eggshells) do not always mean that you are infested with lice. Nits can stick to hair even when lice are gone, for example, after treatment that kills the lice.

how do I treat head lice effectively?

Most importantly, whatever method you choose to use, make sure you follow the instructions precisely. The most common cause of treatment failure is failing to carry out the treatment properly!

Currently, there are three main ways of clearing head lice. The method you use to treat the lice is often a personal preference. Each method has a good chance of success, but no method is 100% certain of clearing lice.

1. Using an insecticide lotion
These contain malathion or phenothrin. You can also get these on prescription. Shampoo, mousse and crème rinse preparations of these insecticides are not recommended as they do not work as well as lotions.

Insecticide lotions are 80% effective when used properly. Use two applications seven days apart – even though this may be different to what some manufacturers state on the lotion packet. However, it is current advice from UK experts on head lice to give the best chance that the treatment will work. Use the water based preparations if possible, especially if you or your child has asthma or eczema.

2. Using dimeticone lotion
Dimeticone lotion works in a different way to insecticides. It is thought to kill lice by a physical process rather than by any chemical effect. It may block the way the lice pass out water, which kills them. However, it is not thought to kill unhatched eggs, which is why two applications are needed, seven days apart. This method is about 80% effective

3. Wet combing treatment ('bug-busting')
Wet combing is a way of removing head lice without having to use a lotion to kill them. Briefly, the method is similar to detection combing described earlier. You will need a ‘bug busting’ kit which contains the special fine toothed comb. Only one kit is needed for a family and it is washable and reusable.

In this method a combination of liberal use of conditioner (which makes the hair slippery so the lice and the nits cannot grip on) and the combing removes the nits and lice. However, you need to do this at least four times, every four days on each member of the household who has head lice. The number of sessions required depends on the last time you see lice.

The first combing session should remove all hatched head lice, but does not remove eggs. Therefore lice that hatch from eggs after the first session may still be present.
Subsequent sessions clear newly hatched lice. Keep doing the combing sessions every four days until you have had three sessions where no lice are detected.

Once you have had three sessions where you do not see any lice, it usually means that you are then free of lice. This method is about 60% effective.

Other methods
There are various other treatments which have been recommended; such as tea tree oil, quassia, other essential oils, herbal remedies, and electric combs. These methods cannot be recommended over the standard treatments as they have not been scientifically proven.

Children with head lice should carry on going to school or nursery. Head lice do not spread quickly through schools or nurseries. You need close head-to-head contact to pass lice on to others. Young children who are 'best friends' and play closely together may pass lice on. If your child has head lice, a common-sense approach is to tell the parents of their close friends to look out for lice in their children and to share successful treatments.