Strategic testing following toxic epidermal necrolysis allows reintroduction of chemotherapy in a patient with progressive myeloma.

Toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome belong to a family of severe cutaneous adverse reactions that can be life-threatening and carry a risk of significant morbidity and potential mortality in the event of re-exposure. Lifelong avoidance of the culprit agent is mandated, which can lead to the exclusion of multiple medications if the trigger is unclear. This can result in adverse health outcomes analogous to that of a penicillin allergy label. We present a case in which the patient would progress to fatal myeloma in the absence of treatment, however, multiple medications were administered prior to the occurrence of TEN following previous chemotherapy. Available risk stratification tools including human leucocyte antigen assessment and the algorithm of drug causality for epidermal necrolysis scoring system were utilized followed by patch testing which identified a lesser-suspected agent as possibly causative. Further evidence-based in vivo testing and subsequent challenges allowed for the reintroduction of life-saving chemotherapy.