Head Lice Infestation


Head lice (Pediculus humanus capitis) are tiny, wingless insects that generally infest the hair on the head, eyebrows and eyelashes but not the body or pubic hair. There are other types of lice that affects the body and pubic region. Infestation with head lice (called pediculosis) is common amongst kindergarten children and can affect their family members as well.

In addition to adult lice, the affected person’s hair contains nits and nymphs. Nits are the eggs laid by the adult female at the root of the hair shaft, usually at the nape or behind the ears. Nymphs or immature adults hatch out from these nits, 9 to 12 days after egg laying. They feed on human blood from the scalp for about 6 days before maturing into adults.


Movement of the lice and irritation of the skin causes discomfort and itching. This causes a person to scratch the scalp regularly and sometimes aggressively leading to the formation of sores. These sores can then become infected with bacteria and sometimes fungal infections may even start on the scalp. Severe itching can even disturb normal sleep patterns.

Head lice suck blood from the scalp. A chronic infestation (over years) may even lead to anemia. Overall though, head lice infestation does not cause any major complications apart from the discomfort and social stigma associated with having the condition. It does, however, leave the skin on the head prone to infections and in very severe cases of infections even lead to hair loss.


Head lice spread primarily by direct contact such as during sports activities and among people in close proximity to each other. Within the home environment, sharing a bed may contribute to the spread of head lice amongst family members. To some extent, it could be transferred by sharing hair combs, hair accessories, scarves and clothes. Coming in contact with shed hair that was infested with nits can be a cause of infestation.

Several schools have a “no nit” policy under which children cannot return to school until they are nit-free. However, head lice do not pose major health hazards or reflect a person’s hygiene at home or school. Other members of the household should also be included in the treatment to control the infestation. Washing the objects used by affected individual with hot water (60ºC), drying with hot air, dry-cleaning and vacuum cleaning of furniture, carpets and bedding materials can help to prevent transfer.


The main objective of treatment is to kill an existing batch of head lice and prevent population restoration from the nits that have been already laid.

Treatment includes topical applications of hair oil and/or shampoos containing pyrethrin, permethrin, lindane and malathion as the active ingredients. Wet combing with nit combs, after washing hair with anti-lice shampoo helps to eliminate the dead or slowly-moving lice.

Since these medications do not definitely eradicate all the lice, various conservative measures need to be carried out for weeks after the all the nits seem to have been destroyed. The person should be cautious and checked regularly for another infestation.

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