allergic fungal rhinosinusitis an attempt to resolve the diagnostic dilemma objective to resolve the diagnostic dilemma of allergic fungal rhinosinusitis afrs an increasingly recognized type of chronic rhinosinusitis crs in spite of extensive studies controversy exists regarding the etiologic characteristics pathogenesis and diagnosis of this entitydesign prospective comparative studysetting department of otolaryngologyhead and neck surgery postgraduate institute of medical education and research chandigarh indiapatients seventy consecutive patients with crs with or without polypsmethods patients were evaluated by detailed clinical examination computed tomography ct skin test against aspergillin antigen 47 patients and histopathologic and mycologic monitoring based on the presence or absence of allergic mucin m and mycelial element f in the sinus the patients were divided into 4 groups mf likely afrs group mf likely eosinophilic mucin rhinosinusitis mf likely sinus mycetoma and mf crs from other causes the different parameters were compared in these 4 groupsresults thirtysix patients were categorized in the likely afrs group 12 with eosinophilic mucin rhinosinusitis 4 with sinus mycetoma and 18 with crs from other causes despite considerable overlap among different groups the following parameters were significantly more associated with afrs group type 1 hypersensitivity p05 charcotleyden crystals p001 bony erosion p001 and heterogeneous opacity with sinus expansion on ct scan p05 the above results were further validated in those patients for whom all investigations were conducted n 47 the significance of these 4 parameters with regard to afrs was reconfirmed in those 47 patientsconclusions to diagnose afrs important findings should be considered in addition to the detection of fungal elements and allergic mucin charcotleyden crystals type 1 hypersensitivity bony erosion and heterogeneous opacity with sinus expansion on ct the last 3 of these parameters may predict afrs preoperatively