The allocation of leprosy patients into paucibacillary and multibacillary groups for multidrug therapy, taking into account the number of body areas affected by skin, or skin and nerve lesions.

In Nepal, the setting up and maintaining of reliable services for slit-skin smears has proven difficult. A clinical classification system for leprosy has therefore been developed to assist in the allocation of patients to either paucibacillary or multibacillary groups for the purpose of multiple drug therapy (MDT), using 9 body areas: head (1), arms (2), legs (2), trunk (4). Patients with more than two areas of the body affected are grouped as multibacillary (MB) and those with only one or two areas affected are paucibacillary (PB). Using a computer simulation model and the data of 53 patients registered at Green Pastures Hospital (GPH) in Pokhara and 703 field patients from the Western Region, different clinical classification systems were evaluated with regard to their sensitivity, specificity, and predictive value for MB or PB classification, as compared with the histological classification for the GPH cases and the bacteriological classification for the field patients. The sensitivity and specificity of the body area system in present use were 93% and 39%, respectively. The low specificity is due to MB overclassification. The sensitivity of the WHO classification system without skin smear facilities is 73% (the difference with the body area system is significant: p < 0.05, McNemar's test). Our histology findings confirm previous publications indicating that, while some borderline-tuberculoid (BT) patients may outwardly have a 'PB appearance' and be skin-smear negative, their nerve biopsy and sometimes skin biopsy may show a 'MB' picture. This is the first publication discussing a 'body area system' for the purpose described, including diagrams of the areas used. In Nepal it has proved easy to use and teach and its use may be justified in other control programmes which implement MDT, particularly if slit-skin smear services are unreliable or nonexistent.