Increase in the incidence of dapsone hypersensitivity syndrome--an appraisal.

There has been an increase in the reports of dapsone hypersensitivity syndrome (DHS) in the past few years, coinciding with the introduction of multidrug therapy (MDT) for leprosy world-wide. The exact cause of this phenomenon is not clear. We report four cases of DHS observed among 252 leprosy patients on MDT and one case of DHS in a patient taking dapsone for nodulocystic acne in the Dermatology Department of the Osmania General Hospital, Hyderabad, India, between June 1997 and January 1999 with few unusual features. In two of these five patients maculopapular rash was severe and progressed to erythroderma. Introduction of MDT in 1982 has not only decreased the prevalence of leprosy but also brought about a positive change in the attitude of people which increased the voluntary reporting of leprosy patients. This, coupled with improvements in organization of leprosy control and awareness among medical personnel of DHS, are probably the most important reasons for the increased reporting of DHS in recent years.