What is a lice infestation?

A lice infestation is a population of small parasites that live on the human body. The three types of lice that exist are head lice, body lice, and pubic, or crab, lice. All three forms of lice spread by skin-to-skin contact and can spread quickly. While they are all called “lice,” pubic lice are a different species of insect from head and body lice.

Body lice can carry diseases, but they are very rare in the United States. Head lice and pubic lice never carry disease. All forms of lice can be irritating and are contagious. It’s best to treat them early on before they spread.

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

Head lice attach to hair on the head and lays eggs at the base of a hair strand. They’re the most common form of lice and are contagious by close contact.

Body lice live on clothing and move to the body to feed. They’re most common on people with poor hygiene, as they can be easily eliminated by regularly bathing and washing of clothes.

Pubic lice mainly live on pubic hairs but 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 spread to other people through sexual contact.

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

Itching and irritation occur because the lice feed off blood in the human body.

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

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 because of the increased likelihood of exposure.

Lice spread through direct contact. Lice can’t fly or hop, and can only spread by touch, when they quickly crawl to another body. Head lice live a short time (less than 24 hours) off the body, so they may be transferred on shared items that contact the head. This is a less common means of spread than direct contact.

Head lice are attracted to clean hair and aren’t a sign of bad hygiene. Body lice, which carry disease, often spread in places where there’s crowding and poor hygiene. Pubic lice usually spread by sexual contact with a person who has them.

Pets can’t carry lice. Some forms of lice can be transferred through pillowcases, clothing, and toilet seats, but the occurrence of this is quite low. Classroom carpets can’t transfer live head lice either except when children nap close together on the carpet.

Most forms of lice infestation are visible to the naked eye, but sometimes a doctor will need a magnifying glass to see live lice or their egg sacs, which are also called nits.

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

You need to treat lice infestations to eliminate them. Without treatment, lice are still multiplying and will continue to populate the body until they become overwhelming.


You can treat most lice infestations with topical medications. These usually come in the form of shampoo or body soap that you must thoroughly apply to the affected area. Both prescription and over-the-counter (OTC) medications are available.

Wet combing

Some people try to control head lice through a process called wet combing, which 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 it’s unlikely to eliminate the infestation completely.

Alternative therapies

Home remedies such as the following are thought to kill head lice if applied thickly and left on overnight, but these products aren’t clinically proven to be effective. They include:

  • mayonnaise
  • olive oil
  • hair gel
  • petroleum jelly

Prescription and OTC lice medications are more likely to cure the 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 separate treatment and people who have them may have a different outlook. See your doctor immediately if you’ve recently had lice and don’t feel well.

Minimize physical contact with other people, especially in schools, to avoid head lice. Take action at the first sign of infestation so that you don’t infect other people.

Maintain proper hygiene at all times to prevent a body lice infestation. Wash your clothing regularly and avoid contact with people who don’t bathe.

Be selective with your sexual partners to prevent a body lice infestation. Check their genitals before committing to intercourse, or ask them to go to a clinic for testing.