Tuberculosis and Leprosy: Classical Granulomatous Diseases in the Twenty-First Century.

Leprosy and tuberculosis are chronic mycobacterial infections that elicit granulomatous inflammation. Both infections are curable, but granulomatous injury to cutaneous structures, including cutaneous nerves in leprosy, may cause permanent damage. Both diseases are major global concerns: tuberculosis for its high prevalence and mortality, and leprosy for its persistent global presence and high rate of neuropathic disability. Cutaneous manifestations of both leprosy and tuberculosis are frequently subtle and challenging in dermatologic practice and often require a careful travel and social history and a high index of suspicion.