Leprosy: tuberculoid reactional episode developed early after multidrugtherapy was initiated in patient initially diagnosed as multibacillary

Abstract

A 66 year old male complained of loss of sensation in the right toe during 10 years. Six months ago, he presented an erythematous plaque in the right arm, and a biopsy from this lesion showed multibacillary leprosy. Multidrugtherapy for multibacillary leprosy (MDT-MB) was begun, and after 15 days the plaque showed edema and erythema, with necrosis and ulceration. A crop of new erythematous and edematous lesions developed in the skin. A biopsy of one of these lesions showed a reactional tuberculoid leprosy pattern with baciloscopy 3+/6+ (fragmented bacilli). The appearance of the first plaque coincided with a recent diagnosis of diabetes mellitus. During the reactional episode, the patients presented malaise, fever and mild jaundice. The authors discuss the pathogenesis of these events and suggest a previous downgrading phase due the progressive bacillary proliferation with inhibition of cellular immunity by the capsular antigens produced by the solid and viable bacilli. The colonization of the cutaneous area where the new reactional lesions developed may have been previous to MDT treatment, without clinical manifestation. It is possible that the death and fragmentation of the solid bacilli (caused by MDT) exposed new antigenic
epitopes, wich stimulated the constitutional immunecellular response of the patient. The presence of high antigenic levels and effective immune response would produce a granulomatous tuberculoid reaction, highly destructive to the tissues.