Head lice are tiny wingless insects about the size of a sesame seed that live in the hair of humans and animals where they feed on blood by biting the skin. Lice are not dangerous, and do not spread disease, but their bites can cause itching and sometimes skin irritation.
Children are often affected by head lice and nits, the eggs laid by lice in their hair. The nits hatch after several days, producing more lice.
How are head lice spread?
Head lice can be passed between children by contact with personal items, for example shared combs and brushes.
The spread of lice among preschool and school children is common and should not be seen as a sign of poor hygiene.
Lice need warmth and blood to survive. They do not live for long on clothing, bedding or personal items.
What are the symptoms of head lice?
Lice often cause itching of the skin, but this is not always the case. Bites can cause the skin to become red and irritated, which can be made worse by scratching.
You can see the lice and nits if you look closely at your child’s head and scalp. Nits look like tiny white dots attached firmly to the hair. They cannot be brushed or flicked off the hair, but must be physically removed with fingers or fingernails.
How do I know if my child has head lice?
Your child may not have an itchy scalp if they have head lice, and an itchy scalp is not a sure sign of head lice. So the best way to find them is to follow a weekly routine of scalp and hair examination:
Step 1: Using a normal comb, spread hair conditioner through your child’s dry, untangled hair. The hair conditioner briefly stuns the lice to make them easier to catch (lice usually move very quickly, so you might not see them).
Step 2: Using a special metal fine-toothed nit comb (available from the supermarket or chemist) and comb sections of hair from the roots to the tips, systematically combing the entire head. Nits and lice become trapped by the fine teeth of the comb.
Step 3: Wipe the conditioner (and lice and nits) from the comb onto a paper towel or tissue.
Step 4: Examine the tissue and the comb for any sign of lice and nits.
Step 5: Repeat the combing to cover the hair on each part of the head twice.
Step 6: If lice or eggs are found, you will need to take steps to treat the head lice to get rid of them.
What is the best treatment for head lice?
The most effective treatment involves repeating the hair conditioner and combing process until no head lice have been found for at least 2 weeks. This covers the time it can take for any undetected nits to hatch and produce more head lice.
You might need to use your finger nails to dislodge any nits from your child’s hair that escaped the comb and that are 15 mm or less from the scalp. Any further away than that and the nits will not hatch — they will be dead, or will have already hatched.
An added advantage of the hair conditioner-combing process is that it avoids the use of strong chemical pesticides on your child’s skin.
Chemical treatment of head lice
There are chemicals you can buy at the chemist that kill head lice and are known to be safe for children aged more than 6 months, but there is no single chemical treatment that will work for everyone. Lice can develop resistance to the chemicals.
If you decide to use a chemical, it is important that you follow the instructions closely that come with it. You will need to repeat the chemical method within 7 days, as most treatments don’t kill the eggs. The only way to test whether the treatment has worked is to use a nit comb and look for any live lice. If it hasn’t worked, don’t use the same chemical again — switch to another chemical, or use the comb and conditioner method.
What can be done to help prevent lice?
Prevention of head lice among young children is difficult. Lice move between them by head to head contact during play, and can survive for some hours on combs and brushes. One step to minimise the spread of head lice is to avoid sharing brushes and combs.
Learn more here about the development and quality assurance of healthdirect content.
Last reviewed: April 2019