Head Lice Causes, Symptoms, and Treatments

What causes head lice infestation?

Head lice infestation is medically known as 'pediculosis capitis.'
Head lice infestation is medically known as ‘pediculosis capitis.’

Lice (singular: louse) are tiny insects (known as parasites) that are most commonly found on the head (scalp). Hence, they are also referred to as ‘head lice’. The other sites where lice can be seen are behind the ears and on the back of the neck.

Head lice infestation is medically known as ‘pediculosis capitis.’ It is caused due to the spread of lice from one person to another through ‘head-to-head’ (hair-to-hair) contact. Head lice cannot fly or jump but can crawl at a rapid pace on the scalp. They feed on the blood of the person whom they have infested.

What are the signs and symptoms of a head lice infestation?

The most common symptom of head lice infestation is intense itching, which is an allergic reaction to the saliva of the lice. Other signs and symptoms include:

  • Feeling that something is crawling on the head
  • Light brown bugs (head lice) moving swiftly on the scalp
  • Yellow, brown, pin-sized lice eggs (nits) glued to the hair
  • Red bumps (sores) on the scalp, head, or shoulders

Some children may also have

  • Swollen nodes (glands) on the neck
  • Pink eye (an eye infection)

It is possible that children may have head lice on the scalp but do not develop any of the signs and symptoms for several weeks.

What is the treatment of head lice infestation?

Getting rid of lice completely is a troublesome process and needs patience.

A head lice infestation will usually take about 4 to 6 weeks to clear up even with treatment.

The doctor will initially advise using over-the-counter (OTC) products that kill lice and some of the nits in the scalp of the child. The instructions written on the bottle or product information leaflet should be read before using the product.

OTC medications:

  • Permethrin 1% (Nix): This medication is available in the form of lotion, which needs to be applied to the hair for 10 minutes followed by hair wash. It kills only the lice and not the nits. Hence, the application needs to be repeated after 9 to 10 days to kill the hatched eggs before they can produce new eggs.
  • Pyrethrin in combination with piperonyl butoxide (A–200, Pronto, R&C, Rid, Triple X)

After applying any of the OTC lotions, it is necessary to comb the hair from the roots to the tips to remove any lice. This should be done once in a day to remove all the dead lice and their eggs.

Prescription medications:

If OTC medicines have failed to eliminate the lice, the doctor may recommend any of the prescription medicines that include:

All the members of the family need to be treated because they may have been infested with head lice as well. The other general measures to stop the spread within the family/house include:

  • Use of the hot water cycle of the washing machine to wash clothes
  • Dry cleaning of the clothing that is not washable (coats, hats, scarves, etc.)
  • Storing or dry cleaning all clothing (such as comforters), which cannot be washed, and then placing them into a sealed plastic bag and keeping them away for at least 2 weeks
  • Soaking combs and brushes for 1 hour in rubbing alcohol or washing it with soap and hot water
  • Vacuuming the floor and all the furniture in the house

How can head lice infestation be prevented?

It is difficult to prevent the spread of lice amongst school children because there is so much contact that happens between them. However, here is what can be instructed to the children:

  • To keep the garments away from other children's garments (by hanging on a hook)
  • To avoid sharing personal items, such as combs and hats
  • To not lie on the beds or couches that have been used by other children


What percentage of the human body is water? See Answer
Head lice. Available at: https://www.cdc.gov/parasites/lice/head