Bullous drug reaction (also known as a "Bullous drug eruption,"[1] "Generalized bullous fixed drug eruption," and "Multilocular bullous fixed drug eruption"[2]:554) most commonly refers to a drug reaction in the erythema multiforme group.[3]: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.[3]:129 The primary skin lesions are large erythemas (faintly discernable even after confluence), most often irregularly distributed and of a characteristic purplish-livid color, at times with flaccid blisters.[2]:554