Hospitalized patients present a complex scenario where several medications, an unclear timeline, and varied clinical presentation convolute arrival at an accurate diagnosis. The case discussed here exemplies the difculty of diagnosing DRESS syndrome [1]. The patient was notably given intravenous vancomycin for more than 10 days to treat osteomyelitis prior to rash onset [1]. Antihistamines, the typical therapy for RMS, were ineffective, and the rash spread to cover the legs, trunk, and upper extremities [1]. Rash morphology included diffuse erythema to violaceous patches with periorbital sparing and bilateral conjunctival injection, lymphadenopa­thy, facial edema, and mucosal ssuring [1]. Initial labs showed leukocytosis, eosin­ophilia, electrolyte abnormalities, and elevated creatine, while a punch biopsy demonstrated morphology suspicious morphology for DRESS syndrome, including eosinophils [1]. Although vancomycin is implicated in DRESS syndrome, more common inciting agents include antiepileptics, sulfonamides, and allopurinol [1]. Furthermore, cross-reactivity between vancomycin and other glycopeptide antibiot­ics such as teicoplanin and telavancin is shown to induce DRESS syndrome [8, 9]. The common heptapeptide core present in all glycopeptide antibiotics is implicated in cross-reactivity; however, this remains controversial due to demonstrated tolera­bility to vancomycin post-teicoplanin-induced DRESS [9]. Genetic predisposition contributes to the risk of these reactions; specically, the HLA-A*32:01 variant in European populations is strongly linked with vancomycin-associated DRESS syn­drome [9, 10]. HLA testing could improve patient safety and prevent high-risk drug reactions [10].