2.1 Design and participants
We conducted a retrospective control study among patients with AR and AH in the XX Hospital. Participants enrolled from Jan 2020 to Jan 2021. AR patients were diagnosed with a positive skin prick test and the diagnosis was based on the Allergic Rhinitis and its Impact on Asthma guidelines [6]. AH was diagnosed by ear, nose, and throat specialists based on history and endoscopic physical examination[3]. The adenoid size was recorded using fiberoptic nasal endoscopy by assessing the percentage of choanal obstruction: grade I: 0 to 25%; grade II: 26 to 50%; grade III: 51 to 75%; and grade IV: 76 to 100% [7]. Detailed history of allergic conditions was obtained for each patient. This study was approved by the ethics committee of XX University (XJT2020- J112).