Relapsed Immune Thrombocytopenic Purpura Following COVID-19 Vaccination in a Patient With Autoimmune Cytopenias.

Immune thrombocytopenic purpura (ITP) is a rare autoimmune condition characterized by isolated thrombocytopenia in the absence of an identifiable secondary cause. While most cases respond to first-line therapy, relapsed or refractory forms, particularly in patients with coexisting autoimmune disorders, pose significant diagnostic and treatment challenges. Recent reports have identified rare instances of autoimmune cytopenias following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccination, raising concern for potential immune reactivation in predisposed individuals with prior immune dysregulation. We present the case of a 68-year-old male with a history of ITP and autoimmune hemolytic anemia who developed a severe relapse of thrombocytopenia, epistaxis, and suspected gastrointestinal hemorrhage shortly after coronavirus disease 2019 (COVID-19) vaccination. Despite initial treatment with corticosteroids, intravenous immunoglobulin, and platelet transfusions, the patient experienced a second relapse requiring escalation of care with additional immunosuppressive therapy and close hematologic follow-up. Ultimately, his condition improved with a multimodal approach and coordinated outpatient management. This case is clinically significant due to its temporal association with COVID-19 vaccination and the relapsing nature of ITP in the setting of systemic autoimmunity. It underscores the importance of early recognition, timely intervention, and vigilant monitoring in preventing life-threatening complications. The report adds to a growing body of literature highlighting the need for individualized care strategies and post-vaccine surveillance in patients at heightened risk of autoimmune reactivation.