Clinical and histological activity after short duration multi drug therapy for leprosy

The WHO recommended short duration multi drug treatment (MDT) regimens were adopted for treatment of leprosy in Sri Lanka since early 1990. Although the relapse rates after this short duration MDT is very low according to the data published by WHO, in clinical practice significant number of patients present with persistent or clinically active lesions and relapses. This study was carried out on leprosy patients who had been diagnosed and completed their recommended MDT for 6 months for paucibacillary (PB) Ieprosy and 12 months for multibacillary (MB) leprosy. Clinical and histopathological activity graded as active, resolving and inactive were studied in these patients by doing skin biopsies and thorough clinical examination. In the PB group (17 patients) at the end of the treatment, 3 (1.77%) showed clinically active disease, 1 (6%) showed resolving lesions and other 13 (76%) were clinically inactive. Histopathologically 5 (29%) showed active disease and 12 (71%) were inactive. In MB group (22 patients) 7 (33%) showed clinically active disease, 3 (14%) showed resolving Iesions and 12 (54%) were clinically inactive. But histopathologically there were 9 (41%) patients with active lesions and other 13 (59%) were inactive histologically. The study emphasized that although the short duration MDT was aimed at increasing patients compliance and cost effectiveness, there may be incomplete resolution of the disease histologically more than clinically and this was more significantly seen in MB patients than the PB patients. It also showed that the clinical resolution did not correlate well with the histological activity in a significant number of patients. Considering these factors we recommend careful follow up of these patients with clinical and histological active disease, over a long period of time, with serial skin biopsies and microbiological evaluation and where necessary continue the treatment for an additional period of 6 - 12 months, especially in MB type.