What Is It?

Body lice are small, parasitic insects found on the human body or on clothing. These creatures are very similar to head lice, but they typically do not infest the head. Instead, they spend most of their life in an infested person’s clothing, crawling onto the skin to feed on the host’s blood one or more times a day. Female lice lay their eggs on the seams of clothing near the skin, where body heat allows them to hatch in about a week. A female louse (a single lice) can lay up to 300 eggs in her lifetime at a rate of about nine or 10 per day. Eggs require temperatures between 75 and 100 degrees Fahrenheit to hatch, and take between three and five weeks to develop into adults.

An infestation with body lice usually causes intense itching. Where the lice have been feeding, small welt-like marks often develop, along with redness and swelling. In certain people, infestations can cause hives even on areas of the skin not infested directly. In underdeveloped countries, body lice may transmit trench fever, relapsing fever and epidemic typhus due to poor sanitation and overcrowding.

Body lice are apparent in the clothing of an infested person. Lice in all stages of development can be found, especially along the seams of clothes worn close to the body. Someone infested with body lice typically will have 10 or fewer active lice on their skin at any one time, since the lice only return to the skin surface to feed. Body-lice infestation is more common in the winter months, when people may wear layers of clothing. This creates a warm, moist environment perfect for lice. Wearing the same garments without washing for prolonged periods of time increases the risk of infestation.

Body-lice infestations can persist indefinitely without treatment. With treatment, the condition can be eliminated immediately.

Body lice are spread by direct person-to-person contact or by contact with infested bedding or clothing. To prevent infestation, avoid sharing clothes and bedding and close contact with an infested person. It is not necessary to quarantine infested people to avoid spreading body lice. It is important to remember that body lice can survive for a day or two on clothing that is off the body, so avoid contact with clothing or other items that recently have been in contact with an infected person.

Treatment of body-lice infestation involves removing infested clothing and bedding, washing it in hot water, then drying it in a clothes dryer set on high heat. Simply treating clothes and bedding may be enough to eliminate infestation since body lice typically do not remain on the host. However, a pesticide that can be applied to the body may be needed to ensure that the lice have been eliminated completely. Products are available both over-the-counter and by prescription.

If you suspect body-lice infestation, you should call your doctor’s office to discuss treatment options if the infestation is active. Applying pesticides to the body involves certain risks that may not be necessary.

The prognosis for body-lice infestation is excellent once the condition is treated, as long as the lice did not transmit another infection such as epidemic typhus.

Diseases and Conditions Center

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.