Translational Research in Pediatric Specialities Area, Division of Allergy, Bambino Gesù Children's Hospital, IRCCS, Piazza Sant'Onofrio, 4, 00165 Rome, Italy. Pediatric Unit and Emergency, University Hospital Consortium Corporation Polyclinic of Bari, Pediatric Hospital Giovanni XXIII, 70126 Bari, Italy. Department of Medicine, University of Verona, 37129 Verona, Italy. Pediatric Unit, ASST Mantua, 46100 Mantua, Italy. Allergy Unit, Department of Pediatrics, Meyer Children's University Hospital, 50139 Florence, Italy. Department of Human Pathology in Adult and Development Age "Gaetano Barresi", Allergy Unit, Department of Pediatrics, AOU Policlinico Gaetano Martino, 98158 Messina, Italy. Department of Pediatrics, Pediatric Clinic, Fondazione IRCCS Policlinico San Matteo, University of Pavia, 27100 Pavia, Italy. Department of Pediatrics, AOU Ospedali Riuniti Ancona, Presidio Ospedaliero di Alta Specializzazione "G. Salesi", 60126 Ancona, Italy. Pediatric Department, Latisana-Palmanova Hospital, Azienda Sanitaria Universitaria Friuli Centrale, 33100 Udine, Italy. Department of Health Science, University of Florence, 70126 Florence, Italy.