Diagnosis of Leprosy: Current Updates and Future Directions

Leprosy is a chronic infectious granulomatous disorder caused by Mycobacterium leprae, chiefly affecting skin and peripheral nerves. It is the only known bacteria to infect nerves. Clinical diagnosis of leprosy is made when any of the three cardinal signs defined by the World Health Organisation is present. However, leprosy has varied presentations necessitating laboratory diagnostic methods for diagnosis as well as treatment initiation and monitoring. Slit-skin smears and histopathology form the basic diagnostics of maximum utility, while neurological studies, cytology and imaging have significant specific roles. Novel molecular and serological tests are of value in the diagnosis of early, indeterminate, and paucibacillary leprosy, and for screening of asymptomatic contacts. Molecular methods have in addition found an important place in diagnosis of drug resistance in leprosy.