An international collaborative case-control study of severe cutaneous adverse reactions (SCAR). Design and methods.

A multicenter international case-control study has been designed to elucidate the etiology of Stevens-Johnson syndrome and toxic epidermal necrolysis (TEN). Although these diseases occur rarely, the morbidity is high and the mortality for TEN is of the order of 30%. These serious dermatologic conditions have often been linked to exposure to drugs. Infective and autoimmune diseases, as well as other non-drug risk factors, have also been postulated to be of importance in increasing the risk. The design and methods are described, with particular attention to the unique challenges for an epidemiologic study of these conditions.