Causes

Leprosy is caused by the bacterium Mycobacteriumleprae. 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 has 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
• Muscle weakness
• Numbness or lack of feeling in the hands, arms, feet, and legs

Exams and Tests

• Lepromin skin test can be used to tell the two different forms of leprosy apart, but it is not used to diagnose the disease
• Skin lesion biopsy
• Skin scraping examination

Treatment

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.

Outlook (Prognosis)

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.

Possible Complications

• Disfigurement
• Muscle weakness
• Permanent nerve damage in the arms and legs
• Sensory loss

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've 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

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).

Alternative Names

Hansen's disease

References

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.

Ernst JD. Leprosy (Hansen's disease). In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier. 2011: chap 334.

Updated: 4/24/2012

Reviewed by: Linda Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine; 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, Medical Director, A.D.A.M., Inc.