Leprosy is a disease that has been known since biblical times. This infectious disease causes skin sores, nerve damage, and muscle weakness that gets worse over time.
Leprosy is caused by the bacterium Mycobacterium leprae. It is not very contagious and it has a long incubation period (time before symptoms appear), which makes it hard to know where or when someone caught the disease. Children are more likely than adults to get the disease.
Leprosy has two common forms: tuberculoid and lepromatous. Both forms produce sores on the skin. However, the lepromatous form is most severe. It causes large lumps and bumps (nodules).
Leprosy is common in many countries worldwide, and in temperate, tropical, and subtropical climates. About 100 cases per year are diagnosed in the United States. Most cases are in the South, California, Hawaii, and U.S. islands.
Effective medications exist. Isolating people with this disease in "leper colonies" is not needed.
Drug-resistant Mycobacterium leprae and an increased numbers of cases worldwide have led to global concern about this disease.
A number of different antibiotics (including dapsone, rifampin, clofazamine, fluoroquinolones, macrolides, and minocycline) are used to kill the bacteria that cause the disease. More than one antibiotic is often given together.
Aspirin, prednisone, or thalidomide is used to control inflammation.
Diagnosing the disease early is important. Early treatment limits damage, prevents a person from spreading the disease, and allows the person to have a normal lifestyle.
People with long-term leprosy may lose the use of their hands or feet due to repeated injury because they lack feeling in those areas.
When to Contact a Medical Professional
Call your health care provider if you have symptoms of leprosy, especially if you have had contact with someone who has the disease. Cases of leprosy in the United States need to be reported to the Centers for Disease Control and 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).
Renault CA, Ernst JD. Mycobacterium leprae. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2009:chap 251.
Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.