aPediatric Unit, Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia

bPediatric Clinic, Fondazione IRCCS Policlinico San Matteo, Pavia

cPediatric Unit, Rho and Garbagnate Milanese Hospital, ASST-Rhodense, Milan, Italy

Correspondence to Amelia Licari, University of Pavia, Pediatric Clinic, Fondazione IRCCS Policlinico San Matteo, p.le C. Golgi 19, 27100 Pavia, Italy. Tel: +39 0382502629; e-mail: [email protected]