Toxic Epidermal Necrolysis Superimposed on Severe Drug Rash With Eosinophilia and Systemic Symptoms Complicated by Fatal Hemophagocytic Lymphohistiocytosis: A Case Report

Drug rash with eosinophilia and systemic symptoms (DRESS) is a severe cutaneous adverse reaction (SCAR) characterized by an extensive skin rash associated with visceral organ involvement, fever, eosinophilia, atypical lymphocytosis, and lymphadenopathy. Toxic epidermal necrolysis (TEN) is a more severe, distinct adverse cutaneous reaction that causes extensive necrosis and detachment of the epidermis, involving over 30% of the body surface area (BSA). Hemophagocytic lymphohistiocytosis (HLH), a form of excessive immune activation, is known to be associated with SCARs such as DRESS. We present a peculiar case of overlap between different SCARs to reiterate their gravity, a severe form of DRESS triggered by the use of allopurinol overlapping with the aggressive TEN possibly from interaction with vancomycin administered for severe sepsis, which was complicated by a fatal case of HLH.