Multibacillary nerve histology in clinically diagnosed borderline tuberculoid leprosy patients.

The classification of leprosy into multibacillary (MB) and paucibacillary (PB) patients in almost all clinics is entirely dependent on clinical examination. In a study of 21 patients clinically classified as borderline tuberculoid (BT) and, therefore, belonging to the PB group, skin smears and skin and nerve biopsies were examined. Four patients did not have any histopathological evidence of leprosy. Skin smears showed that 1 patient was positive for acid-fast bacilli (AFB), 2 skin biopsies belonged to the borderline lepromatous (BL) category and showed AFB in their lesions, and AFB were present in 10 nerve biopsies classified as BL. It is possible that reported relapses among PB patients may be in those patients with demonstrable AFB in the lesions, including nerves. A careful follow-up study of this particular group of patients after PB multidrug therapy is suggested to resolve this question.