Leprosy - A Review

Leprosy is divided into paucibacillary and multibacillary types, depending on whether bacilli are present in the skin smear. In tuberculoid leprosy, a strong cell-mediated immune response results in isolated lesions and histologically granulomatous lesions where no bacillus is present. In lepromatous leprosy, poor cell-mediated immunity results in diffuse lesions in which numerous bacilli are present. Low-dose dapsone monotherapy led to the development of dapsone resistance in the 1970s; but with the introduction of WHO multi-drug therapy, the incidence of leprosy has declined dramatically. There have been relapses both after dapsone monotherapy and WHO multi-drug therapy. Persisting organisms have been found even after high dose regimen and in clinically cured patients. Continual surveillance is therefore important. Promising new drugs include minocycline, sparfloxacin, and clarithromycin.