IV.1. Upper airways: Allergic fungal rhinosinusitis (AFRS)
AFRS is a unique form of immune-mediated non-invasive fungal rhinosinusitis exhibiting prominent Th2 responses, eosinophilic inflammation, and IgE responses (78). Its prevalence is definitely higher in arid and tropical climates, such as in the Asia-Pacific region, Australia, Thailand, Malaysia, India, the Middle East, Saudi Arabia, North Africa, and Southeastern and Southwestern parts of the US, especially the Mississippi basin (79,80). Climate influence is prominent, as demonstrated by a prevalence of 0.4% in Northern US states compared to over 10% in Southern ones. A. fumigatus is the most frequent fungus involved in AFRS (4,79,80).