Head lice and nits

Head lice are tiny insects that live in hair. Nits are the empty egg cases attached to hair that head lice hatch from.

Head lice are a common problem, particularly in school children aged 4 to 11.

They're largely harmless, but can live in the hair for a long time if not treated and can be irritating and frustrating to deal with.

dark hair and scalp showing red spots and nits
Head lice nits and bites. https://dermnetnz.org/

Signs of head lice

Head lice can be difficult to spot, even when the head is closely inspected.

They're very small whitish or grey-brown insects that range from the size of a pinhead to the size of a sesame seed.

Less reliable signs of head lice include:

  • small white eggs or nits (egg cases) in the hair behind the ears or at the back of the neck
  • an itchy scalp
  • a rash on the back of the neck
  • feeling as though something is moving in the hair

How to spot head lice

The only way to be sure someone has head lice is to find a live louse by combing their hair with a special fine-toothed comb. This is called detection combing.

You can buy detection combs from your local pharmacy, supermarket or online. Combs with flat-faced teeth spaced 0.2 to 0.3mm apart are best for removing head lice, although combs with smaller gaps can be used to remove eggs and nits (egg cases) after treatment.

Detection combing can be carried out on dry or wet hair. Dry combing takes less time, but wet combing is more accurate because washing with conditioner stops head lice from moving.

Wet detection combing

To use the wet detection method:

  • wash the hair with ordinary shampoo
  • apply plenty of conditioner
  • use an ordinary, 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 edge of the teeth lightly touching the scalp
  • draw the comb down from the roots to the ends of the hair with every stroke, and check the comb for lice each time – remove lice by wiping the comb with tissue paper or rinsing it
  • work through the hair, section by section, so that the whole head of hair is combed through
  • do this at least twice to help ensure you haven't missed any areas
  • continue until you find no more lice

If you find head lice, you should check the rest of your family. Treat everyone found to have head lice on the same day.

Dry detection combing

To use the dry detection method:

  • use an ordinary, 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 edge of the teeth lightly touching the scalp
  • draw the comb down from the crown to the ends of the hair with every stroke
  • look for lice as the comb is drawn through the hair. If you see a louse, trap it against the face of the comb with your thumb to stop if being repelled by static electricity
  • comb each section of hair 3 or 4 times before moving on to the next section
  • continue until the whole head has been combed through

How to get rid of head lice and nits

Treatments to get rid of head lice are available to buy from pharmacies, supermarkets and online.

The main treatments are:

  • lotions and sprays
  • wet combing

Everyone with head lice in your household should be treated on the same day.

If a treatment doesn't work the first time, you can:

  • try it again
  • try a different treatment
  • get advice from your school nurse, health visitor, pharmacist or GP

Lotions and sprays for head lice and nits

There are several different products that can be applied to the scalp and hair to kill head lice, including:

  • dimeticone 4% lotion or lotion spray – applied and left for 8 hours (usually overnight)
  • dimeticone 4% spray gel – applied and left for 15 minutes
  • mineral oil and dimeticone spray – applied and left for 15 minutes
  • isopropyl myristate and cyclomethicone solution – applied and left for 5-10 minutes

Some treatments need to be done twice – 7 days apart. This makes sure that any newly-hatched lice are killed.

Detection combing should usually be done 2 or 3 days after finishing treatment, and again another 7 days after that, to check for any live head lice.

Always check the pack or leaflet to see if a product is suitable for you, particularly if:

  • you're pregnant
  • you're breastfeeding
  • your child has head lice and is less than 2 years of age

Your pharmacist can recommend a suitable treatment and advise you on how to use it correctly if necessary.

When to get professional advice

Your pharmacist can advise you about treatments for head lice and nits if you're not sure which is best for you or your child.

Make sure you carefully follow the instructions that come with the treatment you choose.

Find your nearest pharmacy

You can get advice and treatment on head lice and nits directly from a pharmacy.

Pharmacies

How head lice are spread

Head lice are spread by direct head to head contact. They climb from one person's hair to another's.

Head lice:

  • can't fly, jump or swim
  • are very unlikely to be spread by objects like hats, combs and pillows
  • don't have a preference for dirty, clean, short or long hair
  • only affect people
  • can't be caught from animals

Once detached from the hair, head lice will usually die within 12 to 24 hours.

Preventing head lice

It's very difficult to prevent head lice.

You may want to consider regular detection combing if you're concerned about your children or yourself. For example, on a weekly basis.

Lotions and sprays don't prevent head lice and should only be used if a live louse has been found in your or your child's hair.

Staying off work or school and washing clothing and bedding on a hot wash is unnecessary, as it's unlikely to help prevent the spread of head lice.

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Source: NHS 24 - Opens in new browser window

Last updated:
18 January 2023