Allergic Fungal Rhinosinusitis

Allergic fungal rhinosinusitis (AFRS) is characterized by chronic inflammation dependent on the Th2 immune response and is considered a specific subtype of CRS. It can be distinguished from other subtypes by the presence of hypersensitivity, sinus expansion, nasal polyps, and the characteristic occurrence of eosinophilic mucin along with fungal hyphae. The diagnosis of AFRS primarily follows the criteria established by Bent and Kuhn. The development of AFRS is believed to be influenced by the dysregulation of innate immunity and a defective, diminished epithelial barrier, leading to persistent type 2 inflammation triggered by fungal antigens, which distinguishes it from other forms of CRS inflammation. AFRS can exhibit a gradual development of clinical symptoms, commonly including nasal obstruction, facial pressure, hyposmia or anosmia, and postnasal drip. Additionally, patients may experience symptoms associated with bony expansion and sinus remodeling, such as proptosis, decreased visual acuity, blurred vision, diplopia, and cranial nerve palsy. The current gold standard for managing AFRS consists of functional endoscopic sinus surgery and postoperative steroid nasal rinses, focusing on eliminating mucin and fungal debris. Biologic therapies are emerging as promising treatment options for AFRS. Follow-up of AFRS cases plays a significant role in identifying features that may predict recurrence.