Classification of leprosy – From past to present

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, characterized by varied clinical presentation. The various clinical manifestations in leprosy are the results of the variations in the tissue response of the host to the leprosy bacilli in the body in genetically susceptible persons. After entering in the body the bacteria either kill or multiply according to the immune status of the body. According to the degree of resistance of the body, the disease manifests in two extreme forms one with a localized disease and second with generalized form. In between the two, various other forms are present that leads to difficulty and to differences in opinions of different authors. Thus, the classification in leprosy has faced marked difficulties in evolving a satisfactory universally acceptable clinical system of classification. In the literature, different classification systems [Table 1] are available based on clinical, bacteriological, pathological, immunological and therapeutic purposes. The classification of leprosy has undergone a drastic evolution from the time of its inception to the current scenario of the disease.