Pediatric Institute of Southern Switzerland, Ospedale San Giovanni, Bellinzona, Switzerland. Università della Svizzera Italiana, Lugano, Switzerland. Pediatric Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy. Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy. Unit of Clinical Pharmacology, Department of Biomedical and Clinical Sciences L. Sacco, "Luigi Sacco" University Hospital, Università di Milano, Milan, Italy. Department of Dermatology, Ente Ospedaliero Cantonale, Ospedale Regionale di Lugano, Lugano, Switzerland. Department of Internal Medicine, Ente Ospedaliero Cantonale, Locarno, Switzerland. Pediatric Cardiology Unit, Department of Pediatrics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.