Lotions to Clear Head Lice

What are the treatment options for head lice?

Currently, there are three main ways of clearing head lice:

• Using an insecticide lotion.
• Using dimeticone lotion, a lotion that works in a different way to insecticides.
• Wet combing treatment (often called 'bug-busting').

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. This leaflet discusses anti-lice lotions. Wet combing treatment is discussed in a separate leaflet.

Insecticide lotion

Treatment with insecticide lotions has been used for many years. Insecticides are chemicals that kill insects. Lice can be cleared in about 8 in 10 cases by using an insecticide lotion. You can buy an insecticide lotion from pharmacies. There are various brands. The active ingredient is usually malathion or phenothrin. You can also get these on prescription. Carbaryl is another insecticide lotion that is only available on prescription. (Shampoo, mousse and creme rinse preparations of insecticides are not recommended as they do not work as well as lotions.)

Insecticide lotions come in water or alcohol bases. In general, water based lotions are usually recommended as they are safer. Also, some people with asthma, eczema, or broken skin cannot use alcohol based lotions.

Note: if you do use an alcohol based lotion, remember it is flammable. Therefore, do not use it near naked lights, cigarettes, fires, or flames. Be careful to keep children who have alcohol lotion in their hair away from fires.

Follow the instructions on the packet. This may include the following:

• Apply the lotion to dry hair. Part the hair near the top and pour a few drops onto the scalp. Rub well into the hair. Part the hair again a little further down and repeat. Repeat this until the scalp and roots of the hair are saturated. Apply down to where a pony tail band would be. Leave on for 12 hours (overnight) and then wash off. Each person needs about 50ml of lotion, and up to 150ml if the hair is long and thick.
• Do not use a hairdryer to dry hair after applying lotion.
• Re-apply the same lotion after seven days. Although lice are usually killed by one application, not all eggs may be. The second application makes sure that any lice that hatch from eggs which survived the first application will be killed before they are old enough to lay further eggs. This advice - to use two applications seven days apart - 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.
• Inspect the hair by detection combing 2-3 days after the second application. If you find any live head lice, despite treatment, then see a doctor or nurse for advice.

One problem with insecticide lotions is that some lice are now resistant to some insecticides. This is one reason why the treatment is not successful in every case. Some areas of the country have policies which advise on which insecticide to use based on the known 'resistance pattern' of the lice in the area. In addition, there is a possible small risk that repeated use of insecticides may be harmful. Therefore, some parents are not happy to use repeated applications of insecticides on their children. However, one course of two applications, seven days apart, is thought to be very unlikely to cause any harm.

Dimeticone lotion

Dimeticone has recently been found to clear head lice. It is a silicone based product and is not classed as an insecticide chemical. Dimeticone has a good safety record and is widely used in cosmetics and toiletries. Dimeticone is applied in a similar way to insecticide lotions as described earlier. As with insecticide lotions, you need to apply the same lotion twice - seven days apart. Each application is left on for at least eight hours (overnight) and then washed off.

Dimeticone 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. (The second application makes sure that any lice that hatch from eggs which survived the first application will be killed before they are old enough to lay further eggs.)

A recent research study showed that lice can be cleared in about 7 in 10 cases by using dimeticone lotion. The downside to dimeticone is that it is a relatively new treatment with only this one main research study to back up the claim that it works well. Hopefully, more studies will be done to confirm that it is an effective treatment.

Do family and friends need treatment?

Only if they have head lice. All people in the same home, and other close 'head to head' contacts of the previous 4-6 weeks should be contacted. Tell them to look for lice and treat if necessary. (It used to be advised to treat all close contacts even if they had no symptoms. This has changed to just treating people who have head lice.) All people with head lice in the same home should be treated at the same time. This stops lice being passed around again.

What about school?

Children with head lice should carry on going to school. Contrary to popular belief, head lice do not spread quickly through schools. Alarming 'head lice letters' from schools are usually unhelpful. 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.

Some other points about head lice

• Use an anti-lice lotion only when you are sure that you or your child have head lice. Do not use them to prevent head lice, or 'just in case'. Frequent use may cause a build up of small amounts of the active ingredient in the body. The risk of harm from this is very small, but it is best to use anti-lice lotions only when lice are present.
• A common reason for head lice to recur in one person is because close contacts (family and close friends) are not checked for head lice, and not treated if they are infected. The treated person is then likely to get head lice back again from untreated family or friends.
• After treatment and the lice have gone, it may take 2-3 weeks for the itch to go fully.
• Nits may remain after lice have gone. They are empty egg shells and stick strongly to hair. They will eventually fall out. If you prefer, a fine toothed 'nit comb' can remove them.