Health Encyclopedia

Leprosy

Definition

Leprosy is an infectious disease that has been known since biblical times. It is characterized by disfiguring skin sores, nerve damage, and progressive debilitation.

Alternative Names

Hansen's disease

Causes, incidence, and risk factors

Leprosy is caused by the organism Mycobacterium leprae. It is not very contagious (difficult to transmit) and has a long incubation period (time before symptoms appear), which makes it difficult to determine where or when the disease was contracted. Children are more susceptible than adults to contracting the disease.

Leprosy has two common forms, tuberculoid and lepromatous, and these have been further subdivided. Both forms produce sores on the skin, but the lepromatous form is most severe, producing large, disfiguring nodules (lumps and bumps).

All forms of the disease eventually cause peripheral neurological damage (nerve damage in the arms and legs) which causes sensory loss in the skin and muscle weakness. People with long-term leprosy may lose the use of their hands or feet due to repeated injury resulting from lack of sensation.

Leprosy is common in many countries worldwide, and in temperate, tropical, and subtropical climates. Approximately 100 cases per year are diagnosed in the United States. Most cases are limited to the South, California, Hawaii, and U.S. island possessions.

Effective medications exist, and isolation of victims in "leper colonies" is unnecessary. The emergence of drug-resistant Mycobacterium leprae, as well as increased numbers of cases worldwide, have led to global concern about this disease.

Symptoms

Symptoms include:

Skin lesions that are lighter than your normal skin color
- Lesions have decreased sensation to touch, heat, or pain
- Lesions do not heal after several weeks to months
Numbness or absent sensation in the hands, arms, feet, and legs
Muscle weakness

Signs and tests

Lepromin skin test can be used to distinguish lepromatous from tuberculoid leprosy, but is not used for diagnosis.
Skin scraping examination for acid fast bacteria

Treatment

A number of different antibiotics are used to kill the bacteria that causes the disease.

Aspirin, prednisone, or thalidomide are used to control inflammation.

Expectations (prognosis)

Early recognition is important. Early treatment limits damage by the disease, renders the person noninfectious, and allows for a normal lifestyle.

Complications

Permanent nerve damage
Cosmetic disfigurement

Calling your health care provider

Call your health care provider if signs or symptoms described here occur, especially following exposure. Cases of leprosy in the United States need to be reported to the Centers for Disease Control and Prevention.

Prevention

Prevention consists of avoiding close physical contact with untreated people. People on long-term medication become noninfectious (they do not transmit the organism that causes the disease).

Review Date:7/25/2007
Reviewed By:Kenneth M. Wener, MD, Department of Infectious Diseases. Lahey Clinic, Burlington, MA. Review provided by VeriMed Healthcare Network.

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