Abstract
RATIONALE: Evolocumab, a novel proprotein convertase subtilisin/kexin type 9 inhibitor, is widely used for intensive lipid-lowering therapy. However, its safety profile in patients with altered gastrointestinal anatomy (e.g., partial gastrectomy) remains inadequately characterized, particularly regarding allergic risks linked to immune microenvironment changes. PATIENT CONCERNS: A 55-year-old male with coronary artery disease and a history of partial gastrectomy received subcutaneous evolocumab (140 mg) post-percutaneous coronary intervention. Within 24 hours, he developed a diffuse erythematous rash with pruritus on the chest and back. DIAGNOSES: Coronary artery disease (status post-percutaneous coronary intervention); allergic rash induced by evolocumab (Naranjo score: 7, WHO-UMC causality: probable). INTERVENTIONS: Evolocumab was discontinued. Intravenous dexamethasone (5 mg/day) and oral cetirizine (10 mg/day) were administered for allergy control. OUTCOMES: Rash and pruritus significantly improved within 48 hours. One-week follow-up confirmed full resolution without hyperpigmentation. LESSONS: Post-gastrectomy patients may face heightened evolocumab allergy risks due to immune dysregulation. Pre-administration assessment of surgical history and close post-dose monitoring are critical.