bullous drug reaction bullous drug reaction bullous drug reaction most commonly refers to a drug reaction in the erythema multiforme group.: 129 these are uncommon reactions to medications, with an incidence of 0.4 to 1.2 per million person-years for toxic epidermal necrolysis and 1.2 to 6.0 per million person-years for stevens–johnson syndrome.: 129 the primary skin lesions are large erythemas (faintly discernible even after confluence), most often irregularly distributed and of a characteristic purplish-livid color, at times with flaccid blisters.: 554 bullous drug reactionother namesbullous drug eruption, generalized bullous fixed drug eruption, multilocular bullous fixed drug eruption: 554 specialtydermatology