Comparison of two systems of classification of leprosy based on number of skin lesions and number of body areas involved--a clinicopathological concordance study.

BACKGROUND AND AIMS WHO guidelines classify leprosy patients for therapeutic purposes into paucibacillary (PB) and multibacillary (MB) leprosy based on the number of skin lesions. An alternative system of classification has been in practice in Nepal from 1985 onwards, based on the number of body areas involved in patients of leprosy. We attempted a clinicopathological approach for comparison of these two systems of classification in leprosy patients for their ability to demarcate patients into groups of PB and MB leprosy. MATERIALS AND METHODS The study included 108 leprosy patients (80 males and 28 females). Complete clinical examination and body charting was carried out in each patient noting the count of skin lesions and the number of body areas involved. Slit skin smears and skin biopsies were taken from an active skin lesion in all patients. RESULTS On analysis, it was observed that there was good clinicopathological correlation between patients with 5 or < 5 skin lesions and 2 or < 2 body areas involved. (Clinical 95% and histological 96%) A similar correlation was also observed in the other group of patients with > 5 skin lesions and > 2 body areas involved, (Clinical 94% and histological 96%). There were almost identical numbers of patients represented in these two groups of classification. CONCLUSIONS Our findings suggest that patients with involvement of 2 or less body areas can be classified as PB leprosy and those with more than 2 body areas involved can be classified as MB leprosy for the purposes of therapy. The study of areas of involvement in leprosy patients not only provides additional patient information but also adds another parameter as a basis for the study of leprosy patients.