Head Lice and Nits (Scalp Parasite Infestation)


Head lice are small, wingless parasites found on the scalp. Head lice (Pediculus humanus var. capitis) infest the head and scalp for food and shelter. They live on scalp and feed on blood. Head lice infestation is a very common problem in schoolgirls between 5 to 11 and their close contacts but can affect almost anyone. Head lice are usually transmitted through close personal contact and shared personal belongings. The condition is medically known as pediculosis and commonly referred to as nits and lice, with nits referring to the louse egg of the immature form of the louse.


Signs and symptoms of a head lice infestation are:

  • Presence of adult lice on scalp, behind the ears, and along the back of the neck
  • Intense itching resulting from an allergic reaction to the saliva of lice injected during feeding
  • Presence of itchy red bumps on the scalp, neck and shoulders
  • Presence of lice eggs called nits on hair shafts


The causes of a head lice infestation (pediculosis)  includes:

  • Head-to-head contact is the most common mode of transmission of head lice. Children get lice in school while playing or interacting closely together and spread it to their family members.
  • Sharing personal items like hair brushes, combs, headphones, hats, caps, scarves and other hair decoration items also spreads head lice.
  • Contact with contaminated clothing, blankets, towels, and pillows may spread head lice.
  • In severe infestations, head lice can also be found on upholstered furniture and may spread to people using them.

The biggest risk factor for developing an infestation is coming into contact with someone with head lice. Cleanliness, personal hygiene, and socioeconomic status play negligible roles in head lice infestation contrary to public opinion.

Head louse picture from Wikimedia Commons


Various over-the-counter products, prescription medications and self-care measures can help eradicate mild to aggressive head lice infestation.

Treatment options are listed below include :

Over-the-counter products

  • Pyrethrin or permethrin-containing shampoos are usually the first line of treatment. These products are fairly efficient in combating lice infestations.

Prescription medication

Substances like malathion, lindane, and benzyl alcohol lotion are often recommended by the doctors to treat severe lice infestation.

  • Malathion is avoided in children less than 6-year old, and in pregnant or breast-feeding women.
  • Lindane may have side effects like skin irritation and seizures and is not recommended for people weighing less than 110 pounds (49.9 kilograms); pregnant or breast-feeding women; and in patients with complaints of seizures; or with HIV infection.
  • Benzyl alcohol lotion may cause seizures in infants. Side effects in older children and adults include irritations of the skin, eyes, and scalp.

Home care

  • Combing wet hair with a fine-toothed brush or a nit comb physically removes the lice.
  • Repeat every three to four days for at least two weeks.
  • method is highly recommended for children under the age of 2 years.


Vacuuming and washing stuffed animals, bedding, and clothing in hot water will kill head lice present on them. The unwashable items can be sealed in an airtight bag for three to four days to kill both live and newly hatched lice in the absence of nutrition. A prompt and thorough removal of head lice and their eggs is the best approach for handling a head lice infestation and preventing its spread.


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