What is head lice?
Head lice are parasites, Pediculosis capitis, that infests the human scalp and feed on blood from there. Many people, usually school children, are affected and the infestation is easily treated and does not usually lead to any complications. Unlike other species of lice infestation like body lice, head lice do not carry any disease and as such are harmless apart from feeling of intense itching and chance of secondary infection of the scalp due to abrasions resulted from itching. Head lice spread from person to person by sharing personal items like combs, hair brushes, towels or direct personal contact (head to head). Medicated shampoo and lotions are available for treatment.
What are the symptoms?
The symptoms of head lice include :
- Intense feeling of itching: when the louse feeds on the scalp blood, it injects its saliva into scalp which is allergic to humans. There may be allergic rashes seen on the scalp, shoulders and neck. Severity of itching increases with recurrent infestations.
- Visible adult lice usually spotted behind the ears and on the back of the neck. Visible lice eggs (nits) remain attached to the base of the hair shaft by means of glue like substance secreted by the mother louse. Both the above symptoms are socially embarrassing
- Usually head lice do not have any ill effect on health, rarely secondary bacterial infection may occur due to abrasion on the scalp due to scratching.
What causes head lice?
The head lice insects lack wings, cannot fly or jump. They usually spread by head to head contact commonly seen in children or by sharing personal belongings (like hair brushes, combs, hats, scarves, towels, pillows and blankets) of a head lice infested person. In contrary to common belief, head lice infestation does not occur due to poor maintenance of personal hygiene.
The life cycle of head lice is about 30 days. The lice lay eggs usually near the base of hair. Environmental temperature plays an important role in location of the eggs on the hair shaft – in colder climate eggs are more close to the scalp and in warmer climates it is further from the scalp. The female lice produces a glue-like substance which helps in the attachment of the eggs to the hair shaft. It usually takes about 14 days for hatching the eggs, after which the shell remains attached to the shaft. It may remain attached to the hair shaft for months unless it disintegrates or is removed.
Anyone who comes in contact with a person having a head lice infestation is at risk. School-going children are more commonly affected along with their care givers. Females are more commonly affected in comparison to males.
How are head lice eradicated?
There are over-the-counter shampoos available (containing permethrin) which can effectively manage head lice infestation. Prescription medicines are required in persistent cases of head lice infestation. Commonly prescribed drugs are :
- Malathion: is not given to children < 6 years old.
- Benzyl alcohol: is not prescribed to children
Combing of wet hair with special fine-toothed is helpful and commonly used in young children. The key should be on prevention and other children in the house need to be constantly monitored.