Fungal rhinosinusitis occurs in different forms depending on race and region. While allergic fungal rhinosinusitis is common in Caucasians, fungal ball (FB) is more common in Asians. However, most cases are reported as unilateral, and clinical data on bilateral FB (BFB) are rare. Therefore, the purpose of this study was to analyze and to compare the clinical characteristics of BFB and unilateral FB (UFB) in Koreans.

Several previous studies have shown that serum 25(OH)D deficiency is associated with increased risk of chronic rhinosinusitis (CRS) in adults and also correlated with disease severity. We aimed to investigate the correlation between serum 25(OH)D level and endoscopy-based CRS in adults using the Korean National Health and Nutrition Examination Survey.