Classification of Leprosy

Diagnosis and classification are two essential points for correct patient management. Correct classification allows proper treatment and alerts of the risk of leprosy reaction and nerve damage. The Ridley–Jopling classification recognizes the complex pathogenesis of leprosy and is based on a spectrum that extends from tuberculoid leprosy (TT), through borderline tuberculoid (BT), mid-borderline (BB), borderline lepromatous (BL), to the poorly resistant lepromatous leprosy (LL). The World Health Organization (WHO) classification, for therapeutic purposes, divides patients into paucibacillary (PB) and multibacillary (MB) on the basis of the number of skin lesions. PB cases have up to five skin lesions in total, whereas MB cases have six or more skin lesions. The two systems are complementary rather than exclusive.