Abstract
Acquired hemophilia A (AHA) is a rare autoimmune disorder with high morbidity and mortality. It results from the development of circulating autoantibodies against factor VIII. AHA can be seen in association with autoimmune vesiculobullous diseases, autoimmune diseases, malignancy, pregnancy, and medications. We report a 68-year-old Thai woman diagnosed and treated for bullous pemphigoid (BP) for 11 months who recently presented with a 3-day history of extensive hemorrhagic bullae and large intra-oral buccal hematoma. Laboratory investigations confirmed a prolonged activated partial thromboplastin time, a low factor VIII level, a high factor VIII inhibitor level, and elevated anti-BPAG180 and anti-BPAG230 titers, confirming the diagnosis of BP associated with AHA. Immunosuppressive therapy with systemic corticosteroids and cyclophosphamide combined with bypassing agents for bleeding control resulted in significant clinical improvement and subsequent negative antibody levels. There was no recurrence after a 7-month follow-up period. Due to life-threatening bleeding in severe AHA cases, early diagnosis and effective treatment in this condition are essential.