How to Treat Head Lice

This page gives information on how to treat head lice. It includes information on conventional medical treatments including insecticide shampoos and hot air as well as information on home remedies with essential oils.

Wet combing is a very important part of head lice treatment and is explained in detail, as well as methods to prevent head lice in you child. You will also find photos of head lice, nits and a nit comb.

If you have a specific question in the list below, go straight to that question by clicking on the link, or otherwise just keep reading.

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What are head lice?

Head lice (or pediculosis capitis) are parasitic insects that live and breed on the human head. They feed on blood from the scalp and this allows them to grow and reproduce. They lay eggs which are called nits. The nits are "glued" to the hair shaft.

The singular version of lice is louse, so you will see head louse if only one is being referred to.

Head lice cannot jump or fly. They are not killed by water, so washing the hair normally or swimming does not get rid of head lice.

Head lice do not carry disease. Anyone can get head lice, however clean you are.

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How do you get head lice?

Head lice infestation occurs by close contact (where the head louse can walk from one head to another) or by direct contact from an infected brush, clothing or pillowcases. As children "get up close and personal" on a regular basis, infection in children is very common.

If there are head lice in your child's school, then she could easily catch them. She may then bring the head lice from school into your home.

Head lice crawl around the hair gripping the hair shaft in their claws. If two heads are close the will move from one person to another. Head lice are not passed to people from animals, so you don't get them from your pets.

Anyone can get head lice. It is not a sign of poor hygiene. It is not because you don't wash or brush your hair enough.

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What is the life cycle of head lice?

Head lice live in human hair and can pass from person to person by close contact of the heads when they walk from one head to another.

Female lice lay eggs near the scalp. They lay up to 10 eggs a day. The egg is laid in an oval shaped capsule (called a nit) that is glued to the hair shaft. As the hair grows, the nit moves further away from the scalp. Eggs hatch between 7 and 10 days leaving an empty case still glued to the hair. These empty cases are often easier to see as they are white nits and not so close to the scalp.

Once hatched a louse will live for 30 - 40 days crawling around the hair and feeding from the scalp 5 or 6 times a day.

Head lice will not survive beyond 48 hours out of the hair.

Knowing the life cycle can help understand how to treat head lice.

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How do I know my child has head lice?

Before considering how to treat head lice, you need to know that your child actually has an infestation. Your child may have symptoms or you may have heard she has been in contact with someone with head lice, so you will have to check her hair - read more

Head lice can make the scalp itchy so at first, you may notice that your child is scratching her head. However, some children won't seem to be so bothered and may not scratch at all.

The nits can look like dandruff, particularly after the egg has hatched and the dead egg case becomes white. However, it is firmly glued to the hair so will not flake off like dandruff.

You see the lice or the nits (which are the lice eggs in a capsule) in the hair.

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How do I look for head lice and nits?

Look for nits on the hair shaft and also look for live head lice walking through the hair. The best places to see them are behind in the ears and in the nape of the neck at the hairline. Also check the crown of the head.

Look at the hair under a bright light and with a magnifying glass if you have one - the lice don't like bright lights. Part the hair and check it in sections.

Alternatively use a nit comb which is more effective and quicker. Part the hair and comb in sections. After each stroke with the nit comb (starting at the scalp and moving out), wipe the comb on a piece of white paper to see if you have got any nits or lice. You can comb the hair wet or dry - read more

If you find nits on the hair shaft within 6mm (about 1/4 inch) of the scalp, this is active infection that requires treatment. Nits that are more than 10 mm (about 1/3 inch) from the scalp are probably dead, so this is not active infection and doesn't need treatment if there are no live lice and there are no nits closer to the scalp. Nits between 6 and 10 mm from the scalp may be viable so if you haven't treated already, I suggest that you do.

If you see a live louse, then that is an indication of active infection that needs treatment.

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nit combTypical nit comb

What is a nit comb?

A nit comb is a comb with fine teeth that are very close together. You can use any fine-toothed comb or buy a specific nit comb from the pharmacy (as seen in the photo on the right). The space between teeth should be no more than 0.3mm.

With repeated use, the space between the teeth of plastic combs can widen which is why metal combs are often used.

Electronic combs are available. These are used on dry hair and have an electrical charge that kills the louse. 

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What do head lice and nits look like?

The nits (head lice eggs) are small and hard like a grain of salt. They are normally a light grey color. Once laid, the nits are glued to the hair shaft, so you see them on the side of the hair shaft. Once the eggs hatch, the nits are white because the egg case is empty. This often looks like dandruff but it won't flake off like dandruff because it is firmly glued to the hair shaft. Any nits that are more than 10 mm (1/3 inch) from the scalp are empty egg cases.

head lice and nitsHead lice and nits on hair shaft

The adult head louse is a small, flat insect measuring about 2-3 mm (about 1/8 inch) long. They can be hard to see. They don't like light so shining a bright light often causes them to move, making it easier to see them.

The photo on the right shows live lice and hair shafts with nits on them.

Before deciding how to treat head lice, you should consider the following reasons to treat - so only treat when there at least one of the following:

  • a live louse (insect)
  • nits within 10 mm (1/3 inch) of the scalp

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What is head lice treatment?

Head lice need to be treated if you see:

  • a live louse (insect)
  • nits within 10 mm (1/3 inch) of the scalp

When considering how to treat head lice, there are a number of options. Often, your local pharmacy will be able to tell you what lice shampoo is working best for people in your area. There is not one treatment that will always be 100% effective, so look at all the option in the "how to treat head lice" section.

If your child is less than 2 years of age, please use wet combing as pediculicides (insecticides) should not be used in young children. To read more about wet combing, click here.

Conventional Head Lice Treatments include these main groups:

  • Insecticides Shampoos and Hair Treatments - these are also called pediculicides and are applied to the hair usually as a shampoo. These kill the head lice but not kill the eggs (ovicide).
  • Insecticide-free Shampoos - these don't contain insecticide so are safer and can be used more often that insecticide hair products.
  • Anti-parasitic medicines - these are given by mouth
  • Suffocation treatments - these are applied to the hair and cover the lice and the nits so they can't breath and so die
  • Hot air +/- other treatments as above
  • Combing - this is very safe and can be used in children younger than 2 years of age. Combing can be done on wet or dry hair. Combing is also helpful to use in conjunction with pediculicides which the louse but don't always kill the nits (eggs)

How to treat head lice with topical insecticides

Topical agents are those you put on the head like shampoo, lotions and creams. There are several insecticides (pediculicides) that can be used in children older than 2 years of age. Often pharmacies will all tend to use one and only move onto another agent if there is resistance to the first. By doing this, it means that there is likely to be at least one insecticide that works at any one time.

Always follow the directions carefully. If the hair needs to be wet, wash with shampoo but no conditioner and then towel dry before applying the treatment shampoo. Do not wash the hair for at least 2 days after the treatment. Wet comb after the shampoo treatment.

Do not treat if you don't find evidence of infection.

Insecticide treatments include the following:

  • Permethrin 1% - Permethrin has brand names including NIX, Lyderm and A-Scabies. It is often the first choice because it works well and is easy to use and is the lest toxic of the insecticides. It continues to kill newly hatched eggs for a few days. How to treat head lice with Permethrin: Apply the cream to washed hair that has been towel dried. Leave for 10 minutes, then rinse off. Repeat in 7-10 days
  • Pyrethrin or Pyrethrum - brand names include A200, Pronto and RID. These are plant based insecticides that kill lice but not the eggs, so a repeat application after 7-10 days is necessary. How to treat head lice with Pyrethrin: Apply the product to dry hair, leave it 10 minutes before washing out
  • Malathion 0.5% - Malathion has brand names including Ovide, Derbac M and A-Lices. It can be used in children older than 6 years. How to treat head lice with Malathion: Apply on dry hair until the hair is moist and then allow to air dry. Leave on for 8-10 hours before washing off. A further treatment may be necessary after a week. There is a gel that is easier to use - you only leave on for 30 minutes. This is more toxic than the Pyrethrins and Permethrin, so try other options first.
  • Lindane Shampoo 1% - Lindane has the brand name Benhex. It is very strong and should be reserved for cases where other agents have failed. How to treat head lice with Lindane: Wash the hair with a normal shampoo an hour before using Lindane (don't use conditioner). Then shampoo with a small amount of Lindane and leave on for 4 minutes but no longer. Then wash off. Do not repeat this treatment. Do not use in young children and as this is a toxic treatment, I would suggest trying all other methods first

To find out how to treat head lice in children under 2 years of age, click here.

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How to treat head lice with insecticide-free shampoos

  • Dimethicone - this is a silicone product. Brands include Hedrin and Lice MD. They have no insecticides so are safe to use and can be used more frequently than insecticide shampoos. How to treat head lice with LiceMD shampoo: Apply to dry hair and then the hair is "wet combed". The dimethicone which is the active ingredient in LiceMD is a lubricant that allows smooth combing. To read the product leaflet and see pictures of wet combing, click here. To read about Hedrin, click here
  • Benzyl alcohol 5% - Brands include Ulesfia Lotion. How to treat head lice with Ulesfia: Use to wash the hair and the alcohol kills the lice but not the eggs so the treatment needs repeating

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How to treat head lice with anti-parasitic agents

Most treatments for head lice involve lotions or shampoos that are applied directly to the hair. However, Ivermectin is an anti-parasitic drug that can be used. How to treat head lice with Ivermectin: It is given by mouth in a dose of 200 micrograms per kilogram weight. The dose is repeated after 2 weeks in most cases. It has been used in children over 5 years of age without many side effects.

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How to treat head lice with suffocation agents

There are some novel treatments that work by suffocating head lice and their nits. They include:

  • Cetaphil cleanser - this can be easily bought from your local drug store (pharmacy) and is the ingredient in the Nuvo product. How to treat head lice with Cetaphil or Nuvo: Apply the cleanser to the hair, comb out excess and then use a blow dryer to dry the hair. Leave the dried cleanser on the hair overnight and the next day wash it out. Use weekly for 3 weeks. The treatment works by suffocating the lice on the hair as the blow dryer causes the lotion to form a capsule around the lice
  • Dimeticone 4%lotion - this is also known as Hedrin lotion and LiceMD. Hedrin is used as a suffocant. How to treat head lice with Hedrin: Apply Hedrin to dry hair and then let the hair dry naturally. The silicone in Hedrin works by coating the louse and disrupting their ability to function normally. Leave on overnight or for at least 8 hours before washing out with normal shampoo. To read about LiceMD, click here
  • Parasidose - this is a shampoo that is insecticide free. The coco oil in the product coats the lice so suffocating them. How to treat head lice with Parasidose: Apply to dry hair, then left o for 45 minutes before being washed off
  • Oils - such as olive oil, soya oil, sunflower oil. How to treat head lice with oils: Apply the oil liberally to the head and cover with a shower cap. Leave overnight and comb out the next day with a fine-toothed comb. Repeat every four days for 3 weeks
  • Mayonnaise - How to treat head lice with mayonnaise: Apply liberally to the head and cover with a shower cap. Leave overnight and comb out the next day with a fine-toothed comb. Repeat every four days for 3 weeks. The vinegar in the mayonnaise will help break down the glue that hold the nits to the hair shaft and the mayonnaise should smother the lice. This can be messy though, so I would try other options first

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How to treat head lice with hot air

It is known that heat (at least 50 degrees C) will kill eggs and often lice as well. Scientists have studied different ways of delivering heat (hot air) to the head of children.

  • Blow drying hair - this is successful particularly at killing the eggs. Directed blow drying is better than diffuse blow drying. If your child feels the air is too hot, just withdraw the hair dryer to a comfortable level. How to treat head lice with hot air: Blow dry the hair in sections, spending 3 minutes per section. Continue for 30 minutes
  • LouseBuster - this is a customized blow dryer that has a comb as well. It may be found in schools etc. It has the most success rate for all the hot air methods but is not cost-effective for an individual treatment

As blow drying kills the eggs, this is useful to use in conjunction with other methods, but make sure you check directions of any shampoos as some will be inactivated by heat. In those cases, wait a few days before using the blow dryer method.

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What is wet combing?

When considering how to treat head lice, wet combing is probably the most important treatment and should be used even if you use head lice shampoos. First of all, it is the only treatment for children less than 2 years of age.

Combing can be done on dry hair as well as wet, but it is often easier with wet hair particularly if you add a conditioner (which often stuns the lice for about 20 minutes so they are easier to remove). When looking for head lice and nits, combing is often done on dry hair. Dry combing is performed in the same way as wet combing.

  • If you are wet combing, you can:
    • wash the hair and detangle with a normal comb and then comb with a fine-toothed comb as below
    • wash the hair and then apply conditioner - any one will do. Detangle with a normal comb before using the fine-toothed nit comb as below
    • just apply the conditioner (any one) to dry hair and detangle with a normal comb and then use the fine-toothed comb in the manner below
  • Comb the hair in sections from the scalp outwards with a fine-toothed comb (nit comb). After each stroke, wipe the comb on a sheet of white paper so you can see any lice or nits you have removed. If so, put them in the bin.
  • Comb every section at least 5 times
  • You should comb for at least 30 - 60 minutes
  • If you see nits that have not been removed with combing, you can pick them off (nit-pick) between your thumb and forefinger. If you are having trouble removing the nits, spray some white vinegar on the hair first. When applying white vinegar, leave for 30 minutes and then wash off. The vinegar will soften the glue and make it easier to remove the nits between your fingers
  • Comb at least every 3 or 4 days for 2 weeks to break the cycle of the nits, eg. comb on Days 1, 5, 9 and 13

Because the insecticide treatments above (called pediculicides) are not always 100% effective at killing the eggs, wet combing should be used in conjunction with pediculicide treatments in children.

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Are there any home remedies for head lice?

I am often asked how to treat head lice with home remedies. Although there are not a lot of medical studies on these, they have been widely used with good success - view options.

How to treat head lice with a natural remedy

Consider the following:

  • wet combing - this is very natural
  • suffocation with olive oil, or mayonnaise or even vaseline (although the later two can be messy)
  • Essential Oils - click here to see how to treat head lice with essential oils
  • Blow drying hair
  • White vinegar - apply to the hair and leave for 30 minutes. the vinegar can help break down the glue holding the nit to the hair making it easier to nit-pick
  • Look for the Electric Blue Headlice Products - these have a number of essential oils such as tea tree, rosemary, lavendar etc with other agents. The Conditioner, as well as making the hair easier to comb, makes the lice show up as blue so it's easier to see them when wet combing

How to treat head lice with Essential Oils

Essential oils that can kill head lice include:

  • neem oil
  • tea tree oil
  • lavendar
  • rosemary
  • peppermint
  • eucalyptus

Essential oils must be diluted - using a carrier oil. Olive oil and coconut oil based carriers can be useful as they slow down the lice making it easier to find them. Coconut oil may also work by breaking down the exoskeleton of the louse.

Try this treatment:

  • 4 parts neem oil
  • 1 part tea tree oil
  • 2 tablespoons of olive oil
  • Use the mixture above to saturate the head and leave on for an hour, then wash off
  • Follow by wet combing
  • Wait 2 days before washing the hair again. Put a towel on pillows etc to protect them from the oil

Alternatively, try other essential oils in the list above with some tea tree oil in an olive oil carrier.

How to treat head lice with Neem Oil, Tea Tree Oil, lavendar and rosemary

This recipe makes a large amount but it can be stored for up to 6 months:

  • Take 20 tablespoons of lavender and strip back to remove woody parts
  • Take 20 tablespoons of rosemary and strip back to remove woody parts
  • Mix 200 ml of Neem oil and 200 ml of Almond oil
  • Pour the oil mix over the lavendar and rosemary mix
  • Spoon the mixture into a pan and simmer until it starts to bubble
  • Seive through fine muslin
  • Heat and infuse for 20 minutes then strain again
  • Add Tea Tree oil (40ml) and put in a pour bottle with a stopper
  • This mixture can be kept for up to 6 months
  • Apply 2 tablespoons on the hair and leave for one hour before shampooing off

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How can I prevent head lice?

When head lice are around, it can be difficult to prevent them completely but there are measures that will reduce the infestation of head lice.

  • Brush the hair every evening with a firm brush. Get your child to bend her head forward and brush from the head outwards
  • Don't share brushes. Everyone should have their own brush and comb. When there has been infection, soak the brush in hot water for at least 10 minutes
  • Check your child's head for lice and nits every week
  • When there is a head lice problem, check the hair every day and wet comb every 3 days
  • If you find live eggs or lice on one child, check the whole family and treat anyone who is infected
  • Avoid contact with items that may have been in contact with an infected person's head - eg. your child should keep her clothes separate from other children at swimming, school etc
  • Within 48 hours of contact, wash all bed linen in hot water of 50 degrees C and tumble dry for 40 minutes OR if that isn't possible, just avoid these for 72 hours OR put items in a sealed plastic bag for two weeks
  • When you have a head lice infestation, vacuum the bedding and any floor or furniture you child may have been lying on in the last 48 hours
  • Tie back your child's hair if it is long to prevent it coming into contact with other children''s hair
  • Add a few drops of tea tree oil or neem oil to your child's normal shampoo

Do not use head lice treatments to prevent head lice.

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What if head lice come back after treatment?

It depends on how soon the lice come back as to how to treat the head lice recurrence.

  • lice return within 2 days or so. The treatment you used may not be working because the lice are resistant. Try another treatment
  • lice return in 7-10 days. The treatment has probably worked but some nits have survived and hatched. Repeat the same treatment
  • frequent recurrences. You can try a combination of methods so use an insecticide shampoo, then a suffocation method and continue wet combing. Check that you have followed all the advice in the prevention section - read more

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References

  • Center for Disease Control
  • KidsHealth - there are a number of useful leaflets including how to wet comb
  • Pearlman D. Cetaphil cleanser (Nuvo lotion) cures head lice. Pediatrics 2005 Dec;116(6):1612
  • Ameen M, Arenas R, Villanueva-Reyes J, Ruiz-Esmenjaud J, Millar D, Domínguez-Dueñas F, Haddad-Angulo A, Rodríguez-Alvarez M. Oral ivermectin for treatment of pediculosis capitis. Pediatr Infect Dis J. 2010 Nov;29(11):991-3
  • Greive KA, Lui AH, Barnes TM, Oppenheim VM. A randomized, assessor-blind, parallel-group, multicentre, phase IV comparative trial of a suffocant compared with malathion in the treatment of head lice in children. Australas J Dermatol. 2010 Aug;51(3):175-82
  • Guidelines for the diagnosis and treatment of pediculosis capitis (head lice) in children and adults 2008. Guideline Summary NGC-6586. National Guideline Clearing House

To go to the top of the "how to treat head lice" page, click here

To go to the Infection page, click here

To go to the Home page, click here


Last reviewed 8 July 2012

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Dr Maud MD

Dr Maud MD (MBChB, FRACP, FRCPCH), a specialist pediatrician, provides health information and medical advice for parents of babies and toddlers. Read more about Dr Maud.



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