Head lice

Head lice are tiny grey/brown insects which live by sucking blood from the scalp. They 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.

The head louse (Pediculus capitis) affects only humans and cannot be passed onto or caught from animals. Contrary to popular belief, head lice cannot jump, hop or fly but are transferred by close hair-to-hair contact. They are not a sign of dirty hair or poor hygiene; in fact, head lice prefer clean short hair. Head lice are common in school children, but anyone with hair can catch them.

Most people with head lice do not have any symptoms. An itchy scalp occurs in about one in three cases. This is due to an allergy to lice saliva, not due to them biting. It often takes about three months for an itch to develop after you are infected. So, you may not notice that you have head lice immediately and you may have been passing them on to others for some time.

Head lice are difficult to find just by looking in the hair. If you suspect head lice, check the base of hairs for eggs and comb the hair over a piece of white paper to see if you can spot any dark mature lice. Treatment is only needed if you see live moving lice. If you or your children have head lice you should check the rest of the family and alert close friends and your child’s school.


Once infestation is confirmed head lice can be treated at home either using wet combing with conditioner, or medicated lotions combined with a special nit comb available from your pharmacy.

Wet combing method
Wet combing or ‘bug busting’ is a way of removing head lice without using chemical treatments.

This method can be useful but it can also be time consuming, particularly if there is more than one affected child. It relies on removing the newly hatched lice before they mature and lay eggs, thereby breaking the cycle.

Medicated lotions or rinses
A number of products are available which kill lice. Whichever product you use, follow the directions on the packaging very carefully. Babies (under 6 months) and pregnant women should always consult the pharmacist.

Shampoos tend not to be as effective as lotions or mousses as the amount of insecticide they contain is usually much lower (after they have been diluted with water during washing), and they are not in contact with the hair for as long a period.

Lotions come in water (aqueous) or alcohol. Aqueous lotions are the most appropriate if you have asthma, eczema or broken skin. Alcoholic lotions should be avoided in children, asthmatics and pregnant women.

Some tips to follow when using a medicated product:

  • Ensure you cover the whole scalp.
  • Avoid getting the product in the eyes as it will sting.
  • If using a lotion, apply to dry unwashed hair.
  • Leave the product to dry naturally for up to 12 hours (this depends on the product) before
    washing off – refer to the manufacturers instructions.
  • Do not use a hair dryer to dry hair after applying treatment.
  • Re-apply the same treatment after seven days.
  • Inspect the hair using a fine tooth comb to remove dead lice and eggs after using your
    chosen product.


There is no guaranteed way of preventing head lice. Try to use a nit comb every week or so to help detect head lice infection early, therefore if an infestation does occur, you can start treatment quickly and reduce the risk of passing them on to others. Use of a head lice repellent shampoo or spray may help prevent infestation.


The information provided on this website does not replace medical advice.

If you want to find out more, or are worried about any medical issue or symptoms that you may be experiencing, please contact our pharmacist or see your doctor.

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