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Head lice infest the head and neck and usually attach their eggs to the base of the hair shaft. Lice move from one place to another by crawling. Head lice are highly contagious. They spread from one person to another by close contact.

Facts about head lice

They can never hop or fly. Children often bring lice home from school or get them from a maid or any other person at home. Pet animals do not transmit head lice. Head lice infestation is a very common problem in children between 3 and 12 years. It is more common in girls than in boys. Head lice infestation is not related to the cleanliness of a person.

Lice infestation is also called as pediculosis. There are three different types of lice that can infest human beings. This are:

  • Body lice also called as Pediculus humanus corporis
  • Head lice also called as Pediculus humanus capitis
  • Pubic lice also called as Phthirus pubis

Head lice develop through three forms- nits, nymphs and adults. Adult head lice are about 2-4 mm in length. The female lice live for about one month. During this period they lay about 3-10 eggs per day. These eggs get glued to the base of the hair shaft. These eggs or the nits can be seen attached to one side of the hair shaft. These nits cannot be removed from the hair shaft with the fingers. These eggs hatch in 1-2 weeks. Lice are not always visible. But nits can be seen at the back of the head and neck and above the ears like grains of salt. These are sometimes mistaken for dandruff.  Dandruff can be moved along the hair shaft unlike the nits.

Head to head contact is the most important mode of transmission of head lice. They also spread by sharing of combs, brushes, towels, hats, scarves and hair ribbons. The larvae and the adult lice feed on human blood. Only after the infested individual gets sensitized, symptoms start to develop. Intense itching is the most common symptom. The other often seen symptom is irritability. Due to itching, bacterial infection can occur on the scalp. This in turn causes matting together of hair and enlargement of the lymph nodes in the neck.

Treating head lice infestation

Head lice never go away on their own. They have to be treated with appropriate medications. The most important factor in the treatment of head lice is to treat all the members of the family at the same time. Both over the counter and prescription medications are available for the treatment of head lice. All clothes and bed linens that come in contact with the hair should be washed clean with hot water (130° Fahrenheit, 54.4° Celsius). Then these are put in the hot cycle of the dryer for at least 20 minutes. If the clothes and linens cannot be washed by machine, they are dry cleaned.

Combs and brushes should be either discarded or soaked in lice killing medication for about an hour and washed with boiling water. All the treated individuals should be examined again after 2-3 weeks to make sure all the head lice and nits are gone. Even after effectively eliminating the lice and nits, itching may persist for a few more days.

The following are considered important in the treatment of head lice:

  • The first reaction by parents on seeing head lice or nits is getting panicky. Parents should not get panicked as head lice infestation is not a harmful condition.
  • The parents should consult a healthcare provider to confirm the diagnosis though they can diagnose it themselves.
  • It is better the parents inform the school authorities or the day care provider so that they can take necessary steps to check other close contacts for head lice infestation.
  • All the members of the family should be examined for head lice infestation.
  • The treatment of choice is 1% permethrin cream (Nix) rinse. This is applied for 10 minutes. A repeat application has to be done in 7-10 days.
  • Other medications that can be used to treat head lice are natural pyrethrin shampoos, 0.5% Malathion and 1% lindane shampoos. These should also be applied for 10 minutes with a repeat application in 7-10 days.
  • These medications are avoided in children less than 2 years of age. Treatment in these children is by manual removal of lice and nits using fine toothed comb. This is done every 3-4 days on wet conditioned hair for 2 weeks. Wetting the hair makes the lice immobile for sometime.  Conditioning makes it easy to comb the hair.
  • If there is bacterial infection due to scratching which may lead to enlarged lymph nodes in the neck it has to be treated with a course of antibiotics.
  • Brushing and wet combing of the hair should be done regularly.  This minimizes the severity of infestation by reducing the number of lice and the nits. Nits can also be removed with a fine toothed comb after 1:1 vinegar, water rinse or after rinsing with 8% formic acid.

Prevention of head lice infestation

Reinfestation by the head lice can be prevented by taking few precautions. These include:

  • Parents should tell their children to avoid head to head contact while in school, during play and while at home.
  • Children should be told not to share combs, brushes, scarves, towels, helmets.
  • If anyone at home is infested with head lice other members of the family including children should be examined every 3-4 days for the presence of lice and treat them if found.

If after 8-12 hours no dead lice are found and they are found to be as active as before treatment, then it indicates that the medication is not effective. Same medication should not be used more than 2-3 times while treating if it is found to be not working. In this situation a healthcare provider should be consulted for appropriate treatment.

  • Nelson Textbook of Pediatrics – 18th Edition
  • Guide to Child Care- Dr.R.K.Anand