Melkersson-Rosenthal syndrome in an allergic patient successfully treated with fresh frozen plasma.

Melkersson-Rosenthal syndrome (MRS) is a rare and often challenging condition of unknown etiology, typically defined by a clinical triad of peripheral facial nerve palsy, recurrent orofacial edema, and fissured tongue. Its variable presentation and overlap with allergic reactions, mast cell-mediated disorders, and drug hypersensitivity reactions can delay diagnosis and appropriate management. We report the case of a 43-year-old man with a personal long-standing history of recurrent hemifacial and lip swelling associated with facial nerve palsy and a plicated tongue, fulfilling the complete clinical triad of MRS. Extensive laboratory, immunological, infectious, and allergological investigations ruled out alternative diagnoses, including hereditary angioedema and drug hypersensitivity. Histopathological examination of a lip biopsy did not reveal granulomatous inflammation. The disease was refractory to multiple standard therapies, including antihistamines, corticosteroids, epinephrine, antibiotics, and immunomodulatory agents. Administration of fresh frozen plasma at a dose of 10 ml/kg resulted in a rapid and marked clinical improvement within 6 hours. This case highlights a rare complete presentation of MRS and underscores the challenges in diagnosis and management. The favorable response to fresh frozen plasma suggests a potential therapeutic option in refractory cases; however, further studies are required to clarify its role and mechanism of action in Melkersson-Rosenthal syndrome.