1. Paediatric Respiratory and Allergy Unit; “Virgen de la Arrixaca” University Children's Hospital; University of Murcia; Murcia Spain
2. Department of Paediatric Respiratory Medicine; Hospital El Pino; University of Santiago de Chile (USACH); Chile
3. Division of Allergy, Clinical Immunology and Rheumatology; Department of Paediatrics; Federal University of S; ã; o Paulo (UNIFESP); São Paulo Brazil
4. Princess Amalia Children's Clinic; Isala Klinieken, Zwolle, and UMCG Postgraduate School of Medicine; University Medical Centre Groningen; the Netherlands