A high incidence of viable Mycobacterium leprae in post-MDT recurrent lesions in tuberculoid leprosy patients.

The differentiation between relapse and late reversal reaction in post-MDT recurrent lesions in paucibacillary cases of leprosy is difficult under field conditions. 1 Even histopathological studies are of lirnited use.2 Therefore, a therapeutic course of corticosteroid is recommended3 and is used in practice particularly in tuberculoid (paucibacillary) cases presenting with fresh activity in old anel/or appearance of new lesions after release from treatment. This is based on the assumption that a delayed hypersensitivity type reaction to persisting dead bacterial products (antigen), causes late reversal reaction. The present study was carried out to determine whether viable bacteria are present in recurrent lesions of tuberculoid and borderline tuberculoid leprosy cases. The type and activity of the lesions are assessed histopathologically. The results obtained in a small group of 25 patients are presented in this paper.