1. Department of Allergology, Hospital Quirón, Barcelona, Spain
2. Upper Airway Research Laboratory, Department of Oto-rhino-laryngology, Ghent University, Ghent, Belgium
3. Unitat de Rinologia & Clínica de l’Olfacte, ENT Department, Hospital Clínic i Universitari; Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); and CIBER de Enfermedades Respiratorias (CIBERES), Barcelona, Spain