Head lice and nits

Last updated:

Reviewed by:

Dr Bryony Henderson

, Lead GP at Livi

Medically reviewed

Head lice and nits are very common and can affect anyone, particularly school children and families. Head lice have nothing to do with dirty hair or poor hygiene. They can affect short or long hair and are picked up by prolonged head-to-head contact.

What are head lice? 

Head lice are tiny grey-brown insects that can be up to the size of a sesame seed. They can only live on people. Head lice cling to hairs very tightly and feed off the scalp but can be difficult to spot. They lay eggs that hatch after 7 to 10 days. A newly hatched head louse takes around a week to grow into an adult louse that is able to lay eggs. 

Nits are the empty yellow-white eggshells from which head lice hatch. Nits look similar to dandruff, but cannot easily be brushed out.

What causes head lice?

Head lice are caused by close hair-to-hair contact between people. Head lice do not jump or fly, they will walk from one head to another. It takes a single head louse only 30 seconds to move from one scalp to another. 

Head lice die away from hair, so they don’t live for long on pillows or sheets. It’s estimated that they can only live for a maximum of 24 hours away from a human head. However, they can be passed between individuals who share items such as combs, brushes or hats. 

How common are head lice?

Head lice are a common problem in young children, especially school children aged 4 to 11 years old. Head lice are more common in girls or children with long hair. With more hair, there is an increased chance of lice moving into the hair. Whilst it is not possible to completely prevent head lice, tying long hair back will reduce the risk of catching them.

What are the symptoms of head lice?

Some people will not experience any symptoms, but the classic symptoms of head lice include:

  • Itchiness

  • A rash on the scalp from repeated itching

  • Infection of the marks made from scratching

Head lice can, but not always, make your head feel itchy as they feed on blood from the scalp. The itchiness is caused by a skin reaction to the lice bites, saliva, or waste.

Repeated scratching of the scalp can cause a rash, which is vulnerable to infection.

How are head lice diagnosed?

The only way to know if someone has head lice is by finding live lice. You might be able to spot lice by looking through someone’s hair, but it’s easier to find them using a special fine-toothed comb called a detection comb. The fine teeth of the comb are designed to pull out head lice. You can buy these combs from your local pharmacy or online.

How are head lice treated?

Treat lice as soon as you spot them, and be sure to check everyone in the house for head lice. There are several treatments to get rid of head lice which you can buy from the pharmacy or online. You can treat head lice and usually do not need to see a GP. 

Wet combing

Head lice and nits can be removed by using specially designed combs to brush wet hair. This can take a long time to do thoroughly (10 to 20 minutes depending on the length and texture of the hair) and needs to be repeated regularly. 

It’s best to carry this out on day 1, 5, 9 and 13. If head lice are a frequent problem, it can be helpful to use wet combing more regularly (about once a week). Check your family again at day 17 to ensure that the head lice have been treated. 

Medicated insecticide lotions and sprays

These treatments kill head lice in all types of hairs and can be very effective. 

It’s important to know that some of these treatments are not suitable for pregnant or breastfeeding women or for children under 2 years old. 

A pharmacist can help you to find the best treatment options for yourself or your child. You might have to try a few treatments to completely get rid of the eggs and lice. 

With all of these treatments, make sure you carefully follow the instructions. Some preparations require contact with the hair for minutes but others require an overnight treatment.

When should I speak to a doctor?

If you’ve tried to remove head lice and they haven’t gone away after at least one treatment, speak to a doctor.

If your scalp feels sore, you have a rash, or you feel generally unwell with a raised temperature, contact your GP or 111. 

How can Livi help?

A Livi doctor will ask you questions about your symptoms. They’ll make an individual assessment and recommend a treatment.

Last updated:
Reviewed by:
Dr Bryony Henderson, Lead GP at Livi