Head Lice & Nits: Treatments & Causes

Head Lice & Nits: Treatments & Causes

Published: 4th October, 2021 in: Health Health Advice

Head lice are small insects that live on the scalp, feeding off blood. They are around 3mm long, which can make them difficult to spot in the hair. They are parasitic insects meaning they are unable to live without nourishment from a host.

Often thought to be interchangeable terms, nits are actually the eggs from which the head lice hatch. Nits are brown in colour before the lice has hatched and white afterwards. Despite the common misconception, having head lice does not mean that the hair is dirty. Lice are simply spread by head to head contact. 

Find out more about who can get head lice, what causes them and how head lice can be treated at home.

Who Can Get Head Lice?

Head lice are most common in young children however head lice in adults is also common for those with school-age children. 

Head lice are spread via head to head contact therefore a child may pick up head lice at school and pass them on to close family members. You can get head lice at any age but should be especially observant whilst your children are in school or nursery.

If someone in your household has head lice, you should check everyone in the house and alert anybody who they may have been in close contact with. 

What Causes Head Lice?

Head lice infestations are caused by head to head contact with another infected person. They could also be transferred by sharing brushes, hats, combs or towels. 

Lice travel by crawling. They are unable to jump or fly therefore, close personal contact is needed to pass them on. In very rare cases they could crawl from clothing and onto the hair but, hair to hair contact is much more common.

Head Lice Symptoms

There are two main symptoms of head lice:

  • An itchy head - head lice tend to be more active at night therefore itching may be worse at this time. Itching occurs as the insects bite the scalp in order to feed on the blood. 
  • Feeling of movement in the hair - head lice crawl around the scalp and hair; you may be able to feel them moving around

The main way to check if someone has head lice is by using a lice detection comb. They are available to buy from most pharmacies or often come with head lice treatments such as the Hedrin All in One Shampoo. The fine-tooth comb helps to detect live insects in the hair.

Head Lice Treatment

Once you have discovered head lice, you should begin treating it the same day. Leaving head lice untreated gives them more opportunity to be passed onto other people. There are a number of different products that can be used to treat head lice at home. You do not need to visit a doctor to treat lice.

The best way to get rid of nits and lice include:

  • Wet combing
  • Medicated lotions, sprays and shampoos

Wet combing should be carried out using a fine-toothed comb. Before combing, you should wash the hair with ordinary shampoo, apply lots of conditioner and then comb the hair from root to tip. You need to ensure every strand has been combed; this could take anywhere from around 10 minutes to over half an hour. The hair should be combed on days 1, 5, 9 and 13 since discovering lice. This allows any nits (eggs) or newly hatched lice to be removed from the hair. Hair should then be checked again on the 17th day to ensure the lice have been effectively eliminated. 

Some people prefer to combine head lice treatment in order to speed up the process of delousing. The Hedrin All in One Shampoo has been shown to kill lice in as little as 10 minutes. After use, the hair will then need to be combed (comb provided) from root to tip to remove any remaining lice, dead lice and nits. 

Similarly, other treatments are available such as the Lyclear Treatment Lotion or Full Marks Solution. They work to kill lice and eggs in order to remove the infestation. In abnormal cases of infestation, the treatment may need to be repeated. They take between 5 and 15 minutes to work and a detection comb should be used to brush the lice and nits out of the hair afterwards.

Different head lice treatments work in different ways. The Hedrin Once Spray Gel contains Dimeticone and Activdiol. Head lice have a unique strategy of water management. Dimeticone disrupts the louse's process of water management by coating them. This causes them to become permanently immobile and prevents them from getting rid of excess water.  They will die of gut rupture or starvation. 

The Actividiol on the other hand breaks down the louse’s waxy coating that helps them to maintain their internal water balance. Without this, too much water may evaporate from their bodies causing them death by dehydration.

The benefit of ingredients such as this is that they do not pose a risk to those who suffer from asthma, as pesticides can. Head lice have also been known to develop resistance to certain pesticides meaning that treatments that use them may not work effectively.

Explore our full range of head lice treatments.

Preventing Head Lice

There is no treatment for preventing head lice. If you have younger children, you may want to wet comb their hair frequently to check for lice so you can treat them as soon as possible. You should never use medicated lotions or shampoos as a preventative measure for head lice. This can irritate the scalp.


Can head lice live on pillows and sheets?

Head lice cannot live for long periods of time on pillows or sheets. In order to live, lice need to feed off the scalp of a host. Lice can however crawl from one head across a pillow to another person’s head if they are also laying on the same pillow. 

Do head lice like dirty hair?

There is no truth to the myth that head lice like dirty hair. The cleanliness of the hair has no bearing on who is more likely to suffer from a head lice infestation. The length of hair also makes no difference to lice.

Can head lice jump?

Head lice cannot jump. They travel by crawling. This means that head lice cannot jump from head to head. They are transmitted through close personal contact so that lice can crawl from one host to another.

Do head lice bite?

Head lice do bite, yes. Head lice rely on blood from the scalp for nourishment. They bite the scalp in order to feed. This can cause irritation, resulting in an itchy scalp.

How long do head lice live?

Head lice usually die within 12-24 hours after being detached from the scalp and hair.

What happens if head lice are left untreated?

Whilst head lice do not carry diseases and are not dangerous, if left untreated they could be spread to a large number of people. Due to the biting, head lice can also degrade the scalp causing irritation and possible damage to the hair follicles. Head lice should be treated as soon as they are discovered in the hair.

Why does my child keep getting head lice?

Head lice are extremely common in children. At school children spend large amounts of time in the company of many other children. This is naturally the perfect opportunity for lice to spread. Whilst there is no way to prevent lice, you can wet comb your child’s hair frequently in order to spot signs of a lice infestation early.

Explore our full range of head lice treatments and products. Need some advice? Visit one of our pharmacists in-branch.