Histopathology of skin lesions of leprosy before and after fixed duration treatment

Objectives: To study and compare the histopathological features of skin lesions of leprosy before and after fixed duration treatment.
Design: Prospective study. The first 30 newly diagnosed leprosy patients from July2012 who successfully completed fixed duration treatment from our tertiary care institution, and who were willing for a post-treatment skin biopsy were included in this study after obtaining written informed consent. Only those who underwent a pre-treatment biopsy were enrolled in the study. Histological features of pre- and post-treatment biopsies of the skin lesions of leprosy were studied and compared.
Results: The patients who showed an increase or only a slight reduction in granulomas post-treatment compared to the pre-treatment status had clinical and/or histological evidence of lepra reaction at the completion of treatment or had lepra reaction during FDT which was not managed with steroids. Two patients whose pretreatment biopsy revealed only inflammatory infiltrate manifested granulomas in the post-treatment biopsy. 18/30 developed dermal fibrosis after treatment, which was more common in those with considerable post-treatment reduction in inflammation. Five patients showed post-treatment restoration of the reduced basement membrane pigmentation that was noted in the pre-treatment biopsy.
Conclusions: Persistence or increase in granulomas after treatment was not a bad prognostic sign. More prospective studies with a larger sample size analyzing the histological resolution achieved by FDT may improve our knowledge of leprosy.