ABSTRACT Tirzepatide, a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist, is used to treat type 2 diabetes mellitus. While gastrointestinal adverse effects are well established, cutaneous manifestations are less characterized. We report a case of a biopsy-confirmed exanthematous drug eruption associated with tirzepatide. A 74-year-old woman developed profuse watery diarrhea and an intensely pruritic rash shortly after initiating tirzepatide. Over three weeks, the eruption involved the bilateral upper extremities and proximal lower extremities. Histopathologic evaluation revealed superficial dermal perivascular dermatitis with eosinophils and mild epidermal spongiosis. Discontinuation of tirzepatide and topical corticosteroids led to clinical improvement. This case expands the limited literature on systemic dermatologic adverse effects of tirzepatide by demonstrating a biopsy-confirmed exanthematous drug eruption. Recognition of such reactions allows for prompt diagnosis and enhanced patient counseling. This represents one of the first reported biopsy-confirmed exanthematous drug eruptions associated with tirzepatide. Key words: Tirzepatide, GLP-1 receptor agonist, Cutaneous adverse drug reaction, Obesity pharmacotherapy, Dermatologic toxicity
