Relapse in leprosy after multidrug therapy and its differential diagnosis with reversal reaction

Relapse may be caused either by persisters or through reinfection in a patient released from treatment after MDT. Differentiating relapse from reversal reaction is not always easy, on histological and clinical grounds. A therapeutic trial with steroids for 2-4 weeks can be used to differentiate relapse from reversal reaction occurring in the skins. However, if a patient develops nerve function deficit after release from treatment, it is best to initiate antileprosy treatment along with a long course of steroids.