Head lice are tiny insects that feed on blood from the human scalp. There is no link between head lice infestations and poor personal hygiene but they are easily transmitted through hair to hair contact and are therefore are most often seen in young children and their families. The lice and their eggs (nits) are tiny and can be hard to spot with the naked eye, the main symptom of head lice is a persistent itchy scalp. Head lice can be quickly and discreetly treated at home using a medicated lotion and a fine-toothed comb.

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Head Lice Treatments

Advice for Head Lice

What are Head Lice?

Head lice are small white, grey or brown insects that live in human hair and are particularly common in children of school age. They are notorious amongst parents as they can spread quickly between children through head-to-head contact, they do not fly, swim or jump and can only be transferred by touching hair with someone who already has head lice.

Head lice are not a result of poor hygiene or dirty hair. They actually prefer clean hair as it is easier to move through, although they will infect any type or length of hair. Head lice can normally be found at the root of the hair and grow roughly to the size of a sesame seed.

Life Cycle of Head Lice

Female head lice lay eggs (nits) at the root of hair by cementing them to the scalp. The eggs can be difficult to spot at they are extremely small.

Head lice eggs hatch after 7 – 10 days releasing the baby head lice, which then feed on the scalp and grow to full size in around 10 days. They leave the white empty eggs (now known as nits) attached to the hair that grow out with the hair and become more noticeable.

Female head lice can start laying eggs from 9 days old so they need to be removed from the scalp before this point to break the infection cycle.

How do I know if I have Head Lice?

Head scratching is normally the symptom that leads to the discovery of head lice. However, the itching caused by head lice is due to an allergy to the lice, which not everyone has and even if they do it can take up to three months to develop.

Children of school age should be inspected for head lice regularly as well as parents looking out for warnings from their school that head lice may be spreading.

As head lice are only the size of a sesame seed when fully grown, they can be difficult to spot. This is not helped by their normal brown/grey colour helping them to blend into the hair. The best method to check the hair for head lice is detection combing using a fine-toothed head lice comb (like Nitty Gritty).

Detection combing can be done on wet or dry hair, although it tends to work better on wet hair. It traps lice and pulls them out of the hair to allow easy identification and diagnosis. To diagnose an active infestation you must find live head lice, eggs/nits are not enough as these can be dead and left attached the hair after the actual lice infestation has cleared.

See ‘Wet Combing’ in the ‘Treatment’ section below for advice on combing using a fine-tooth nit comb. This can also be done with dry hair although it is usually easier and more effective if the hair is wet.

How do I treat Head Lice?

Head lice are notoriously difficult to treat as they have an extremely high re-infestation rate, especially amongst school children. Combined treatment of wet combing and a head lice lotion or spray can prove effective, however preventative measures must also be put in place to prevent recurrence.

Treatment for head lice now favours using oil or silicone-based products (such as Hedrin) as traditional insecticides now have a high rate of resistance and are becoming less effective.

Remember you should only start treatment if lice head lice are found; eggs/nits alone are not enough to diagnose a head lice infestation.

A typical treatment regime for treating an active head lice infestation is:

Wet Combing

  • Wash the hair using plenty of shampoo, apply generous amounts of conditioner and brush through using a normal comb
  • Systematically work through the hair using a detection comb by placing the bevel-edge lightly against the scalp and drawing the comb all the way down to the end of the hair
  • Check the comb between each stroke and rinse off and head lice that may be present
  • Rinse out the conditioner and repeat the detection combing procedure
  • Repeat this procedure every 3 days for at least 2 weeks to remove newly hatched lice before they can lay eggs

Head Lice Lotion/Spray

Head lice lotions or sprays are the best over-the-counter treatments for head lice and can be used in combination with wet combing to fully treat an infestation. Rinses and shampoos are generally not as effective.

You should ensure you have enough to treat everyone who has a confirmed infestation, taking in account the length and type of their hair. They are normally applied to dry hair and left on for between 10 minutes and 8 hours. You should check the individual products for specific usage instructions.

Head lice treatments do not always kill the eggs so it is normally advised to repeat the application after around 7 days. You should check for live lice around 3- 5 days after using the treatment and again after 10 -12 days although if you are also wet combing this will not be necessary.

It is not normally necessary to see your GP for head lice treatment although persistent infestations may need to be investigated. It is not normally advisable to treat babies under 6 months old, pregnant women or people with asthma or allergies without consulting a healthcare professional.


Head Lice FAQs

  • Head lice crawl from one person’s hair into another’s in close proximity. Head lice do not jump or fly. What’s the best way to detect head lice? Regular examinations using a nit comb like Full Marks Detector Comb or Nitty Gritty comb. Check for head lice if anyone in your family has been in contact with someone who has head lice

  • The thought of head lice alone is enough to make some people itch. Others develop an itching sensation when the louse injects salvia into the scalp while it feeds. This itch can take weeks to develop or not develop at all.

  • Nits are white, empty egg shells that the louse leaves behind when it hatches. They stick to the hairs and can be removed with a nit comb or a pair of tweezers.

  • Ordinary shampoo will not remove head lice. This is because the lice breathe through holes in their bodies called spiracles. During a regular shampoo, they simply close these spiracles until the washing stops, making the shampoo ineffective at killing them.

  • Full Marks Solution is suitable for people who suffer from eczema and asthma, but speak to your doctor or pharmacist for more advice. Derbac M is suitable for use by asthma sufferers and is appropriate for sensitive skin.

  • You can’t prevent children from contracting head lice, but with regular detection combing you can find head lice quickly and destroy them before their population grows.

  • Relapse can happen immediately as treatment doesn’t prevent head lice from being caught. For this reason, ‘contact tracing’ is important since it reduces the chance of immediate relapse.

  • You should conduct ‘contact tracing’ if head lice is caught and inform close relatives, friends and your child’s school. However, your child does not need to miss school while being treated for head lice.

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