Histological assessment of dermal nerve damage occurring during multidrug therapy for leprosy

This is a prospective histomorphological assessment of dermal innervation i n biopsies taken before and after multidrug therapy (MDT) from 41 leprosy p atients: 35 borderline tuberculoid (BT), 3 borderline lepromatous (BL), 3 l epromatous CLL). Biopsies of the same lesions taken before commencement (di agnostic therapy) and at the end of therapy (check biopsy) were compared. H ematoxylin and eosin, immunoperoxidase stain for S-100 protein, and the Hol mes' silver impregnation method for nerve cells and fibers were used. Skin biopsies were classified as having detectable or undetectable nerves. Of 35 patients with BT leprosy, 17 had no detectable nerves in their diagnostic biopsies; in the check biopsies of 13 of these 17, dermal nerves remained u ndetectable, in 2 they were S-100 positive but were Holmes negative. Identi fiable dermal nerves were present in diagnostic biopsies from 18 patients; in the check biopsies 5 of these 18 had no detectable nerves while in the r emaining 13 nerve branches could be detected. The study provides histological documentation of complete damage to dermal innervation in 62.85% (22/35) of patients with BT leprosy, of which 14.28% (5/35) occurred during MDT. Of the patients with detectable dermal innervat ion at the onset of MDT 27.7% (5/18) suffered continuing damage during MDT.