Head Lice

Lice are ecto-parasites, parasites that live on the outside of the body of the victimized host. There are three types of lice that can be found on the human body, head lice, body lice and pubic lice. Head lice are the most common. Lice cause itching, irritation and annoyance. They also transmit many serious diseases such as typhus and trench fever.

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Human head lice are very small, usually about 1/8-inch, whitish color with dark markings on its side. There are three stages to a louse’s life cycle, the nit, the nymph and the adult.

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Nits are lice eggs. The female head lice can lay anywhere between 80 to 140 eggs in its lifetime.

Head Louse (Pediculus humanus capitis)

The nymph is a baby louse and looks similar to an adult louse but is smaller in size. These nymphs usually mature into adult louse after seven days. The mature louse is about the size of a sesame seed and has six legs. An adult louse may live up to 23 days. Adult head lice are very dependent on the host and feeds several times a day. Head lice cannot survive more than a day or two without contact with a host.

How do I know if I have head lice?

The most common symptom of head lice is irritation and scratching of the scalp, behind the ears and around the neck. It can happen that the victim would not feel symptomatically “Itchy.” Combing can be a useful tool in looking for lice because they are hard to spot. Nits (louse eggs) are most easily seen through the use of a black light and an infestation of lice can look similar to dandruff. Unlike dandruff, the nits stick to the hair even after shampooing. Irritation and the “itchy” feeling are the most common effects of the lice. Severe itching and constant scratching can lead to lack of sleep. More serious effects from intense scratching include eczema-like skin eruptions.

How do you acquire head lice?

There are many ways that you can obtain head lice. The most common ways that head lice are passed is through shared sleeping arrangements or by sharing accessories such as: combs, hats, pullovers. Lice can be found on bedding and upholstered furniture and transfer to the next person who lays on that furniture.

What is the treatment for head lice?

First, to prevent head lice, do not share items that go on the head or hair grooming objects, notably combs. Do not come in contact with any furniture or clothing that a person who may have lice has potentially used. Louse or nit combs help remove the infestation but will not be effective unless used in conjunction with other forms of treatment.

See your physician before beginning treatment. Half measures may make matters worse.

In addition to manual removal of lice and after clear and positive identification, lice are also treated with a variety of insecticides. But this is to only be done after there is a positive identification of the parasite. They can be treated with shampoos labeled for use on people. Other shampoos are available by prescription that contains stronger concentrations. Often one must perform a second treatment about ten days after the initial treatment because most products are not ovicidal (they do not kill the eggs). If there is an infestation, make sure to wash multiple times, all items that have been in contact with the infested person.