Drug-induced hypersensitivity reaction presenting as systemic capillary leak-like syndrome with polyserositis: a case report

Background Systemic capillary leak syndrome (SCLS) is a rare disorder characterized by increased vascular permeability leading to third-spacing of fluids and protein. Drug-induced hypersensitivity reactions can mimic SCLS clinically and radiologically. Case Presentation: A 42-year-old Vietnamese man developed abdominal distension, facial edema, and dyspnea after initiation of Helicobacter pylori eradication therapy. Imaging revealed pleural, pericardial, and peritoneal effusions, periportal edema, and interstitial pulmonary edema. Laboratory results showed hyponatremia, hypoalbuminemia, and mild anemia. Autoimmune screening revealed ANA positivity (1:80, speckled) and lupus anticoagulant, though extractable nuclear antigens were negative. The patient improved rapidly with corticosteroids and antihistamines. Conclusion This case highlights a systemic hypersensitivity reaction mimicking capillary leak syndrome, likely drug-induced, and occurring in a patient with subclinical autoimmune predisposition. It underscores the importance of immune surveillance and early immunomodulatory therapy.