Leprosy patient. Historical illustration of a man suffering from tuberculoid leprosy, giving his leg an elephantine appearance. Tuberculoid leprosy (which is not related to tuberculosis) affects the skin and nerves, causing numbness and painless skin lesions. It usually produces fewer lesions than the more contagious lepromatous form of the disease. Both types are caused by Mycobacterium leprae bacteria. Leprosy is only spread by prolonged close contact with an infected person. Symptoms can take from 9 months to as long as 20 years to appear. It is now treatable with anti-bacterial drugs such as dapsone, rifampin and clofazimine.