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Lice Infestation

What Is a Lice Infestation?

A lice infestation is a population of small parasites that live on the human body. There are three types of lice: head lice, body lice, and pubic lice (or crab lice). All three forms are passed on through skin-to-skin contact and can spread quickly.

Body lice can carry diseases, but head lice and pubic lice cannot. All forms of lice can be irritating and are contagious. It is best to treat them early on.

What Are the Types of Lice Infestation?

Lice infestations are classified by the body part they correspond to. Different lice are attracted to different parts of the body.

The head louse attaches to hair on the head and lays eggs at the base of a strand. Head lice are the most common form of lice and are extremely contagious.

Body lice live on clothing and move to the body to feed. They are most common in people with poor hygiene, as they are easily eliminated by regularly laundering clothes.

Pubic lice most often live on pubic hairs, but they can be found elsewhere on the body, including the armpits, chest hair, and facial hair. They lay eggs at the base of pubic hair and are transmitted to other people through sexual contact.

All types of lice infestation are treatable. They are all characterized by itching and irritation as the lice feed off the blood in the human body.

What Causes Lice Infestation?

Lice infestations are spread through direct contact. Lice cannot fly or hop. They can only be transferred by touch, when they quickly crawl to another body.

Head lice are attracted to clean hair and are not a sign of bad hygiene. Body lice, which carry disease, are often caused by crowding and poor hygiene. Pubic lice infestations are usually caused by sexual contact with a person who has them.

Pets cannot carry lice. Some forms of lice can be transferred through pillowcases, clothing, and toilet seats, but the occurrence of that is quite low. Classroom carpets cannot transfer live lice.

Who Is at Risk for Lice Infestation?

School children are at risk of head lice because they come in close contact with other students, through play and other activity. Parents are encouraged to regularly check their children for head lice, especially if they complain of an itchy scalp.

Homeless people, refugees, and other people who live in crowded conditions with poor hygiene and sanitation are at risk of body lice.

People with multiple sex partners may be at risk of pubic lice infestation because of the increased likelihood of exposure.

What Are the Symptoms of Lice Infestation?

Symptoms of lice infestation include:

  • itching at the site of the infestation
  • irritability
  • the presence of egg sacs or lice in hair or on clothing

How Is Lice Infestation Diagnosed?

Most forms of lice infestation can be identified by the naked eye. Sometimes a doctor will need a magnifying glass to see live lice or their egg sacs, commonly called nits.

The only way to confirm an active infestation is to find a live louse on site. The presence of nits may indicate a past population that is no longer active.

How Is Lice Infestation Treated?

Lice infestations must be treated to be eliminated. Without treatment, lice will continue to populate on the body until they become overwhelming.


Most lice infestations are easily treated with topical medications. These usually come in the form of shampoo or body soap that must be thoroughly applied to the infected area. Prescription and over-the-counter medications are available to treat lice.

Home Care

Some patients try to control head lice through a process called wet combing. This involves using a fine-tooth comb on wet hair to pull out nits and live lice. This may reduce the size of the lice infestation but is unlikely to eliminate the problem.

Alternative Therapies

Home remedies such as mayonnaise, olive oil, hair gel, and petroleum jelly are thought to kill lice if they are applied thickly and left on overnight, but they products have not been clinically proven to be effective. Prescription and over-the-counter lice medications are more likely to cure infestation.

What Is the Outlook for Lice Infestation?

With proper treatment, lice infestations should go away quickly. In the case of body lice, some residual diseases may remain after an infestation is gone. These conditions require their own levels of treatment and carry their own prognoses.

Preventing Lice Infestation

To avoid hair lice, minimize physical contact with other people, especially in schools. Take action at the first sign of infestation so that you do not infect other people.

To prevent a body lice infestation, maintain proper hygiene at all times. Wash your clothing regularly. Avoid contact with people who do not bathe.

To avoid pubic lice, be selective with your sexual partners. Check their genitals before committing to intercourse or have them tested at a clinic.

Content licensed from:

Written by: Heaven Stubblefield
Published on: Jan 08, 2014
Medically reviewed on: May 02, 2017: [Ljava.lang.Object;@3423ed98

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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