1. Unit of Pediatrics, “Moriggia-Pelascini” Hospital, Via Pelascini, 3, 22015 Gravedona ed Uniti Como, Italy
2. Department of Pediatrics and Pediatric Emergency “Costanza Gravina”, University Hospital “Vittorio Emanuele-Policlinico”, Via Plebiscito 7674, 95124 Catania, Italy
3. Department of Medical Surgical Specialties, ENT Clinic, University Hospital “Vittorio Emanuele-Policlinico”, Via Santa Sofia, 78, 95123 Catania, Italy