LAUSR

To the Editor: Symmetric drug-related intertriginous and flexural exanthema (SDRIFE) is a curious disorder that has undergone many clinical transformations since first being described by Andersen et al1 in 1984 using the term baboon syndrome. Initially described as a mercury hypersensitivity reaction resulting in an eruption resembling the red-bottomed baboon, this exanthema has expanded in definition with inciting agents, clinical features, and diagnostic criteria. Its prognosis, however, has remained stable and favorable throughout the decades. The condition is almost universally benign and self-limited.1-3 As new cases are reported in the literature and the paradigm of SDRIFE continues to shift, its prognosis also may warrant reconsideration and respect as a potentially destructive reaction. A 39-year-old woman who was otherwise healthy presented to the emergency department after developing a rapidly evolving and blistering rash on the left flank. Hours later, the rash had progressed to a sharply demarcated, confluent, erythematous plaque with central ulceration and large flaccid bullae peripherally, encompassing 18% of the total body surface area and extending from the gluteal cleft to the tip of the scapula along the left flank (Figure 1) with no vaginal or mucosal involvement. The patient recently had completed a 10-day course of amoxicillin–clavulanic acid 2 days prior for a cat bite on the right dorsal wrist. Additional history confirmed the absence of prodromal fever, fatigue, or chills. Inciting trauma including chemical and thermal burns was denied. Potential underlying psychosocial confounders were explored and were unrevealing. Laboratory test results including a complete blood cell count and metabolic panel as well as vital signs were unremarkable except for slight leukocytosis at 14,000/μL (reference range 4500–11,000/μL). A punch biopsy taken from the patient’s left upper back at the time of admission revealed a sparse, superficial, perivascular infiltrate of lymphocytes and rare neutrophils with a largely absent epidermis and an occasional focal necrosis of adnexal epithelium (Figure 2). Immunofluorescence was negative for specific deposition of IgG, IgA, IgM, C3, or fibrinogen. Wound culture also returned negative, and the Naranjo adverse drug reaction probability scale score was calculated to be 4 out of 12, indicating a possible adverse drug reaction.4 Given the extent and distribution of the rash as well as the full-thickness dermal involvement, the patient was transferred to the burn unit for subsequent care. At Symmetric Drug-Related Intertriginous and Flexural Exanthema