Head lice
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Head lice is a medical condition found in humans which involves a hair and scalp infestation attributed to Pediculus humanus capitis, a parasitic insect known as the head louse. While it is mostly the hair on the head and the scalp that is infested, head lice may also infest parts of the body that are hairy. A lice infestation on a human is medically known as Pediculosis.


There are many types of lice infestations that occur in mammals and birds. Humans, in particular are hosts for two kinds of lice: body lice and crab lice. There are hundreds of millions of people who succumb to lice infections each year. While head lice infestations are not fatal nor do they carry infectious diseases, the presence of this small and wingless insect on the heads of children is often a cause for public health concern.

Head lice is a widely endemic infestation, particularly among children between the ages of 3 to 10 years old. Females are more prone to head lice compared to males, with those of African-American descent very rarely succumbing to infestation.

Lice, also known colloquially as nits, infest the head subsist on human blood. They can be passed on from one person to another by contact with the head of a person who is already infested, as these lice can neither jump nor fly.

A louse egg is known as a nit, and they are colored yellow, tan or brown. Adult lice lay these eggs on the shaft of a hair strand close to the surface of the scalp where the body's temperature keeps them warm up to the time they hatch into nymphs between 1 to 2 weeks after the eggs are laid. These nits closely resemble dandruff, however, a person cannot dislodge them by brushing the hair or shaking the head.

When these nits hatch, they develop into nymphs, or baby lice. These grow into adult lice that are roughly the size of sesame seeds and are visible to the naked eye. These lice have mouth parts that resemble tiny needles, which they use to pierce the scalp or the skin of the neck in order to feed on human blood. Unlike other types of lice, head lice do not bury themselves in the skin. They suck blood several times a day from the skin of the scalp or neck and are able to survive for a maximum of 2 days when separated from their host.

The bite of a head louse is very small and can hardly be seen between hair strands. Areas of the scalp, as well as the neck of persons with long hair are regions of the body that head lice frequently bite.
head lice
Image: Head Lice


The most common symptom of a head lice infestation is pruritus, or itching. This symptom occurs on the scalp and neck and is caused by the bites of the adult head louse. The infested person will start to manifest symptoms of itching 3 to 4 weeks after being contaminated, as well as the sensation of things moving or tickling the scalp or the skin of the neck. The bite of an adult louse will also cause inflammation, and scratching these bites may irritate the skin, cause sores to form, and promote the spread of bacterial infection.

In some rare cases, scratching the itchy bites can result in a secondary infection coupled with pyoderma and impetigo. Other rare symptoms include fever and lymph node swelling, accompanied by red and tender skin that may exhibit oozing and crusting where the lymph glands are located.

A head lice infestation is usually caught through contact with the head, clothing, or personal belongings of a person who has head lice. This is particularly true of children between the ages of 3 and 10. Contamination is common during sports activities, slumber parties, at school playgrounds, or at summer camps.

Wearing contaminated hats, coats, uniforms, scarves, or hair ribbons of infested persons will also spread a head lice infestation. So can using towels, combs, and brushes, as well as lying on a couch, pillow, bed, or carpet that has come into close contact with infested hair.


Diagnosing an infestation will involve combing the entire area of the scalp and hair using a special fine-toothed louse comb. The comb should be checked for any signs of adult head lice, nymphs, or lice eggs after each sweep. This method is one of the best ways to detect the presence of lice or a full-blown lice infestation.

People with frizzy or curly hair who are suspected to have head lice will need their hair parted at every 2-centimeters of scalp area to check for the presence of head lice. The skin near the areas of the ear and nape will also need to be checked, particularly if the infested person wears their hair long. To further ascertain that what has been harvested through the louse comb are actually head lice, the results may be examined under a magnifying glass.

When nits are found after combing hair with a louse comb, this does not signify an active lice infestation. There is only a 30% to 40% chance of an active infestation if only nits, or louse eggs are found. There is a good chance, however, that other members of the person's family may have an adult head lice infestation, and their hair and scalp will need to be checked, as well. The absence of living adult lice will mean that a person is not fully infested.


While there are several treatments, including known folk remedies for head lice, there is no medication or method that can get rid of lice eggs or nymphs completely. Some of these treatments include both natural and chemical medications, louse combs, hot air, lotions with silicone content, and the shaving of infested hair.

The usual treatment for head lice are medicated shampoos and rinses. Louse combs are used to remove live adult lice, as well as lice eggs from the scalp and hair strands. To eliminate any traces of lice from personal belongings such as clothes, towels, scarves, hats, or hair ribbons, laundering them under high heat is effective.

There are also anti-louse insecticides that are available in the market today. However, some lice have developed a resistance to some of these products.
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Medication commonly used for these disease:

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