RESUMO
Abstract Erythema nodosum leprosum is a severe immune reaction that complicates the usual course of multibacillary leprosy. There is increased activation of T-cells in erythema nodosum leprosum. Treatment modalities available to date for the management are systemic steroids, thalidomide, methotrexate, cyclophosphamide, azathioprine, minocycline, and apremilast but none of them is promising and safe. Mycobacterium indicus pranii is an atypical mycobacterium possessing strong immunomodulatory properties. The vaccine for this mycobacterium has been shown to have both immunotherapeutic and immunoprophylactic effects in multibacillary leprosy patients. We report a case of chronic recalcitrant erythema nodosum Leprosum which responded to Mycobacterium indicus pranii vaccine without any adverse effects, thereby suggesting its role as a novel therapeutic option in this reaction.