Head lice

Pediculosis is the infestation of hairy parts of the body with the eggs, larvae or adults of lice. Louse infestation is a major problem throughout the world due to difficulty in treatment of the lice infestation.

Life cycle

Lice are ectoparasites that live on the body. Lice feed on human blood after piercing the skin and injecting saliva, which may cause itching due to an allergic reaction. A mature female head louse lays 3-6 eggs/day, also called nits. Nits are white and less than 1 mm size. Nymphs (immature lice) hatch from the nits after 8-9 days, reach maturity in 9-12 days, and live as adults for about 30 days.

Different species of lice feed on different locations like hairs, body and pubic hairs.

Who can get it?

Anyone can be infested with lice under suitable conditions of exposure. Lice is easily transmitted from person to person during direct contact. Head lice infestations are frequently found in school settings, institutions or living in congested homes. Crab lice infestation can be found among sexually active individuals. Body lice infestation can be found in people living in crowded, unsanitary conditions where clothing is infrequently changed or laundered.


Usually the first symptom is excessive itching or scratching in the area of the body where the lice feed. Children may have difficulty in sleeping at night due to intense itching. Scratching can also lead to secondary bacterial infection. Lice also is a vector of 3 kinds of bacterial infections  louse-borne typhus, trench fever, and louse-borne relapsing fever.

On examination of the back of the head, scalp and pubic areas crawling lice and nits can be found.


Medicated shampoos or cream rinses containing pyrethrins or permethrin are advised for treating people with head lice.  Retreatment after 7-10 days is recommended to remove all the eggs. Nit combs are available to remove nits from the hairs.

Treatment should be offered to all the people in contact like family members or close contacts who have been exposed.

Prevention of lice

  • Physical contact with infected individuals should be minimised and sharing of clothes, combs, towels, clothes and beds should be restricted.
  • Proper cleaning of clothes in hot water and hot ironing eliminates body louse and its spread.
  • Detailed instructions regarding use of the shampoos provided and importance of hygiene should be given to individuals.
  • Schools should be instructed to educate the children to not to share combs, headgears or scarfs and to maintain hygiene.
  • Regular direct inspection of children for head lice in body and clothing, particularly of children in schools, institutions, nursing homes and summer camps, is important.
  • All sexual partners of a person infested with pubic lice from within the previous month should be treated. Sexual contact should be avoided until both parties have been successfully treated.

Lice infestation may seem like a very bothersome issue for the individual/child suffering from it but with proper treatment, maintenance of hygiene and avoiding sharing of beds and clothes, the condition can be treated effectively.


Dr Prerna Gaur





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