Leprosy

Alternative names:

Hansen disease

Definition:

An infectious disease, known since Biblical times, which is characterized by disfiguring cutaneous lesions, peripheral neurological damage, and progressive debilitation.

Causes, incidence, and risk factors:

Leprosy is caused by the organism mycobacteria leprae. It is a difficult disease to transmit and has a long incubation period, 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, although these have been further subdivided. Both forms produce lesions on the skin but the lepromatous form is most severe, producing large disfiguring nodules. All forms of the disease eventually cause peripheral neurological damage (nerve damage in the extremities) manifested by sensory loss in the skin and weakness of the muscles. People with long-term leprosy often lose the use of their hands or feet.

Leprosy is common in many countries in the world, and in temperate, tropical, and subtropical climates. Approximately 270 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 have made the existence of leper colonies unnecessary. Recently, the emergence of drug-resistant mycobacteria leprae has caused increased concern about this disease.