Allergic Fungal Rhinosinusitis

Formerly believed to be an upper airway manifestation of allergic bronchopulmonary aspergillosis (ABPA), our understanding of the pathophysiology of allergic fungal rhinosinusitis (AFRS) has significantly evolved over the past several decades. We now recognize these two diseases as distinct entities. AFRS is in part characterized by type 1 hypersensitivity to fungal allergens and is a subtype of chronic rhinosinusitis with nasal polyposis (CRSwNP). While Aspergillus species are implicated, other fungal species have been identified in the disease process. The diagnosis of AFRS is based on clinical findings established by the Bent and Kuhn criteria, which include: (1) type 1 hypersensitivity to fungal allergens, (2) nasal polyposis, (3) radiographic imaging with sinonasal opacification and serpiginous areas of hyperattenuation, (4) eosinophilic mucin, and (5) positive fungal stains. The cornerstone of treatment for AFRS requires multimodality therapy, typically involving nasal saline irrigations, corticosteroids, and surgery, although immunotherapy, antifungals, and biologics may have an emerging role in the management. Herein, we describe our current understanding of AFRS as a disease process, current treatment recommendations, ongoing investigations into the pathophysiology, as well as promising therapeutic interventions.