Abstract
Introduction: Bullous pemphigoid (BP) is the most common autoimmune blistering disorder affecting the elderly population. While the etiology is predominantly idiopathic, physical trauma has been identified as a potential exacerbating factor. Most trauma-induced cases reported in the literature are associated with surgical incisions, burns, or open wounds. The development of generalized BP following a closed fracture, where the skin integrity remains initially intact, is an exceptionally rare phenomenon. The patient experienced a pre-bullous phase starting in June 2025, which significantly progressed to generalized BP following a closed radius fracture in October 2025. Case Report: We report the case of an 85-year-old woman who presented with a generalized blistering eruption 3 months after sustaining a closed fracture of the left radius. Physical examination revealed tense, fluid-filled bullae on an erythematous base involving the trunk and extremities. Histopathological analysis demonstrated a subepidermal blister with eosinophilic infiltration. The diagnosis was confirmed by direct immunofluorescence showing linear deposition of immunoglobulin G and C3 at the dermo-epidermal junction and enzyme-linked immunosorbent assay detecting high titers of anti-BP180 autoantibodies. The patient was treated with a tapering course of systemic prednisone, initiated at 90 mg/day. This regimen led to the cessation of new blister formation within 2 weeks and complete clinical remission with normalization of inflammatory markers within 3 weeks. Conclusion: This case highlights that closed skeletal trauma, even without surgical intervention, can serve as a precipitating factor for generalized BP. The mechanism likely involves the release of sequestered antigens and epitope spreading due to internal tissue damage. Clinicians should maintain a high index of suspicion for BP in elderly patients presenting with cutaneous eruptions following orthopedic injuries to ensure prompt diagnosis and effective management.