Allergic Fungal Rhinosinusitis and the Unified Airway: the Role of Antifungal Therapy in AFRS

Allergic fungal sinusitis (AFS) or rhinosinusitis (AFRS) is a form of polypoid chronic rhinosinusitis that is believed to be due to hypersensitivity to fungal antigens. The disease is characterized by type 1 hypersensitivity to fungal allergens, dramatically elevated total serum IgE, accumulation of thick eosinophil-laden mucin with non-invasive fungal hyphae within the paranasal sinuses, nasal polyposis, and sinus bony remodeling. Because of many clinicopathologic similarities to allergic bronchopulmonary aspergillosis (ABPA), these conditions can be considered analogous examples of disease in the unified airway. However, these conditions rarely occur together and their treatment differs. The treatment of AFRS relies upon surgical removal of fungal hyphae in eosinophilic mucin, while antifungal therapy is used to clear fungi from the airways in ABPA. Several uncontrolled studies suggest there may be some benefit to antifungal agents in AFRS, but randomized trials of topical and systemic antifungal therapies have not shown beneficial results in chronic rhinosinusitis (CRS). Antifungal treatment within the sinonasal cavities does not appear to be an effective approach for most chronic sinusitis, and antifungal therapy for AFRS is unproven.