Eosinophilic Fasciitis in a Young Adult: A Rare Presentation Potentially Triggered by the Epstein-Barr Virus.

Eosinophilic fasciitis (EF) is a rare fibroinflammatory disorder that may mimic systemic autoimmune disease or hematologic malignancy. We report the case of a 19-year-old male patient who presented with progressive swelling, stiffness, and burning pain of the extremities. Laboratory studies were significant for inflammatory marker elevation and polyclonal hypergammaglobulinemia. Epstein-Barr virus (EBV) testing demonstrated a positive polymerase chain reaction (PCR) test and IgG with negative IgM, suggesting prior infection with possible viral reactivation. Imaging showed splenomegaly and diffuse fascial edema, and a deep fascial biopsy confirmed EF. The patient was treated with high-dose corticosteroids with rapid clinical improvement. This case highlights the diagnostic complexity of EF and raises the possibility of EBV as an immunologic trigger.