1 Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Ill. Electronic address: whitney-stevens@northwestern.edu.
2 Rhinology Unit & Smell Clinic, Department of Otorhinolaryngology, Hospital Clínic Barcelona, FRCB-IDIBAPS, Universitat de Barcelona, CIBERES, Barcelona, Catalonia, Spain. Electronic address: jmullol@clinic.cat.