Acquired Hemophilia A in Sjögren's Syndrome: An Uncommon Bleeding Disorder Masked by Antiplatelet Use.

Acquired hemophilia A (AHA) is a rare autoimmune bleeding disorder caused by inhibitory autoantibodies against coagulation Factor VIII (FVIII), leading to spontaneous bleeding in individuals without a prior bleeding history. It is frequently associated with autoimmune conditions, malignancies, or idiopathic causes. Sjögren's syndrome is an uncommon trigger for AHA, and coexisting antiplatelet therapy can obscure the diagnosis. We report the case of a 67-year-old male with ischemic heart disease on dual antiplatelet therapy who presented with melena, hematuria, and ecchymoses for 15 days. Initial evaluation revealed severe anemia and isolated prolonged activated partial thromboplastin time (aPTT) with normal platelet count and prothrombin time. Imaging demonstrated a large bladder hematoma and right knee hemarthrosis. Autoimmune workup was positive for anti-nuclear antibody (speckled pattern) and anti-Ro52 antibodies, consistent with Sjögren's syndrome. Coagulation studies showed markedly reduced FVIII activity (2%) and high-titer inhibitors (256 Bethesda units), confirming AHA. High-dose corticosteroids were initiated; however, the patient developed worsening hematuria, acute kidney injury, and metabolic acidosis, ultimately succumbing to uncontrolled bleeding and multi-organ failure. This case highlights the diagnostic challenge of AHA in patients on antiplatelet therapy, where bleeding may be misattributed to medication effects. Persistent isolated aPTT prolongation should prompt evaluation for coagulation factor inhibitors, especially in the context of autoimmune features. Early recognition and initiation of hemostatic and immunosuppressive therapy are crucial to improve the survival.