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Dispelling the Leprosy Myth

June 1, 2012

By: Rachel Gordon, MD & Karan Sra, MD

Leprosy, or Hansen’s disease, is an infection caused by Mycobacterium leprae and Mycobacterium lepromatosis. This chronic disease has been well-known in popular culture for over 2,000 years, as the infection can cause striking disfigurement and disability. It is not commonly seen in the United States and is often thought of as a disease of antiquity. However, it was estimated by the World Health organization (WHO) in 1995 that 2-3 million people world-wide were permanently disabled because of leprosy.(1)

Contrary to popular belief, leprosy is not highly contagious. Transmission occurs person-to-person via respiratory droplets. Armadillos (9-banded) are carriers of the bacteria and also may spread it to humans if they share a common space (i.e. soil in a garden). It is not sexually transmitted, nor are people infectious after receiving treatment; up to 95% of individuals are naturally immune to developing Hansen’s disease.(2) It is not necessary to quarantine people with M. leprae infections, as effective treatments are available. However, may leper colonies exist in countries such as India, Romania, China, Egypt, and Nepal. There are two that remain in the United States, the residents of which live there on their own accord. In places where leprosy is common, social stigma is a barrier to seeking medical attention and receiving early treatment.

After exposure, the incubation period ranges from a few weeks to decades. Early symptoms of Hansen’s disease are subtle and occur slowly, but may include discoloration of skin (either lighter or darker than surrounding skin) and slight loss of temperature sensation. As the disease progresses, sensation to pain, temperature, and deep pressure are decreased or lost; this occurs on distal limbs first and can lead to injuries. Skin discoloration progresses to the development of raised plaques or nodules that may be anesthetic (without sensation); facial disfigurement and alopecia (loss of hair, including eyebrows and eyelashes) can also occur. Leprosy is typically diagnosed clinically, test such as skin biopsy and mycobacterial cultures aid in diagnosis.

Leprosy is successfully treated with antibiotics. However, antibiotics cannot reverse skin and nerve damage caused before treatment was started, which is why early initiation of treatment is essential. After a person has been successfully treated (i.e. clear of infection), surgery is an option to improve cosmetic appearance and limb function. The best way to avoid infection with leprosy is to avoid close contact with individuals who are untreated. Even in such instance, only about 5% of exposures result in transmission. (2)

If you would like more information about leprosy, visit If you are concerned that you or someone you know may have symptoms of leprosy, make an appointment with your doctor or dermatologist.


  1. WHO (1995). “Leprosy disabilities: magnitude of the problem”. Weekly Epidemiological Record 70 (38): 269–72
  2. “About leprosy: frequently asked questions”. American Leprosy Missions, Inc. Retrieved October 28, 2011