Body lice
Template:DiseaseDisorder infobox
|
WikiDoc Resources for Body lice |
|
Articles |
|---|
|
Most recent articles on Body lice |
|
Media |
|
Evidence Based Medicine |
|
Clinical Trials |
|
Ongoing Trials on Body lice at Clinical Trials.gov Clinical Trials on Body lice at Google
|
|
Guidelines / Policies / Govt |
|
US National Guidelines Clearinghouse on Body lice
|
|
Books |
|
News |
|
Commentary |
|
Definitions |
|
Patient Resources / Community |
|
Patient resources on Body lice Discussion groups on Body lice Directions to Hospitals Treating Body lice Risk calculators and risk factors for Body lice
|
|
Healthcare Provider Resources |
|
Causes & Risk Factors for Body lice |
|
Continuing Medical Education (CME) |
|
International |
|
|
|
Business |
|
Experimental / Informatics |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: Pediculus humanus humanus
Overview
Body lice are parasitic insects that live on the body and in the clothing or bedding of infested humans. Body lice frequently lay their eggs on or near the seams of clothing and must feed on blood and usually only move to the skin to feed. They exist worldwide and infest people of all races.
Pathophysiology
Life Cycle
The life cycle of the body louse Pediculus humanus humanus, has three stages: egg, nymph, and adult.[1]
- Nits are body lice eggs. They are hard to see and are often confused for dandruff. Nits are laid by the adult female and are cemented at the base of the hair shaft nearest the skin . They are 0.8 mm by 0.3 mm, oval and usually yellow to white.
- Nits take about 1 week to hatch (range 6 to 9 days). Viable eggs are usually located within 6 mm of the skin.
- The egg hatches to release a nymph.
- The nit shell then becomes a more visible dull yellow and remains attached to the hair shaft. The nymph looks like an adult body louse, but is about the size of a pinhead.
- Nymphs mature after three molts and become adults about 7 days after hatching.
- The adult louse is about the size of a sesame seed, has 6 legs (each with claws), and is tan to grayish-white. In persons with dark hair, the adult louse will appear darker. Females are usually larger than males and can lay up to 8 nits per day. Adult lice can live up to 30 days on a person’s body.
- To live, adult lice need to feed on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host.
Transmission
Body lice are spread through direct physical contact with a person who has body lice or through contact with articles such as clothing, beds, bed linens, or towels that have been in contact with an infested person. In the United States, actual infestation with body lice tends to occur only in persons, such as homeless, transient persons, who do not have access to regular (at least weekly) bathing and changes of clean clothes.
Associated Diseases
- Typhus
- Louse-borne relapsing fever
Risk Factors
Body lice infestation is found worldwide but generally is limited to persons who live under conditions of crowding and poor hygiene who do not have access to regular bathing and changes of clean clothes, such as:
- The Homeless
- Refugees
- Survivors of war or natural disasters
Diagnosis
History and Symptoms
Common Symptoms
Both of these symptoms are the body's allergic reaction to the lice bite.
Less Common Symptoms
Long-term body lice infestations may lead to:
- Thickening and discoloration of the skin, particularly around the waist, groin, and upper thighs.
- Sores on the body may be caused by scratching. These sores can sometimes become infected with bacteria or fungi.
Physical Examination
Skin
- Eggs and crawling lice in the seams of clothing. Sometimes a body louse can be seen crawling or feeding on the skin.
- Although body lice and nits can be large enough to be seen with the naked eye, a magnifying lens may be necessary to find crawling lice or eggs.
Treatment
Lice infestations are generally treated by giving the infested person a clean change of clothes, a shower, and by laundering all worn clothing, bed linens, and towels. When laundering items, use the hot cycle (130°F) of the washing machine. Set the dryer to the hot cycle to dry items.
Medical Therapy
Sometimes the infested person also is treated with a pediculicide, a medicine that can kill lice; however, a pediculicide generally is not necessary if hygiene is maintained and items are laundered appropriately at least once a week. A pediculicide should be applied exactly as directed on the bottle or by your physician.
Primary Prevention
The following are steps that can be taken to help prevent and control the spread of body lice:
- Regular bathing and changing into properly laundered clothes at least once a week; laundering infested clothing at least once a week.
- Machine washing and drying infested clothing and bedding using the hot water (at least 130°F) laundry cycle and the high heat drying cycle. Clothing and items that are not washable can be dry-cleaned OR sealed in a plastic bag and stored for 2 weeks.
- No sharing of clothing, beds, bedding, and towels used by an infested person.
- Fumigation or dusting with chemical insecticides sometimes is necessary to control and prevent the spread of body lice for certain diseases (epidemic typhus).