Department of Clinical and Molecular Sciences, Polytechnic University of Marche, Ancona, Italy;7. Department of Dermatology, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria;8. Department of Dermatology, Venereology and Allergology, Leipzig Interdisciplinary Allergy Center (LICA)-Comprehensive Allergy Center, University Hospital, Leipzig, Germany;9. Department of Dermatology, University Hospital of Erlangen-Nürnberg, Erlangen, Germany;10. Allergy Campus Hochgebirgsklinik Davos, Davos, Switzerland;11. DM University College Cork and Cork University Hospital, Cork, Ireland;12. Bon Secours Hospital Cork/Department of Paediatrics and Child Health, University College Cork, Cork, Ireland;13. Division of Allergology, University Children's Hospital Zurich, Zurich, Switzerland;14. University Allergy Center, University Hospital Carl Gustav Carus, Technical University Dresden, Dresden, Germany;15. Department for Pediatrics, St. Marien-Hospital, Bonn, Germany;16. Department of Dermatology, Medical Center-University of Freiburg, Freiburg, Germany;17. Allergy Department, 2nd Pediatric Clinic, National and Kapodistrian University of Athens, Athens, Greece

Division of Infection, Immunity & Respiratory Medicine, University of Manchester, Manchester, UK;18. Department of Dermatology and Allergy, Comprehensive Allergy Center, Hannover Medical School, Hannover, Germany;19. Institute for Infectious Diseases and Infection Control, Jena University Hospital, Jena, Germany;20. Division of Allergy, Clinical Immunology and Rheumatology, Department of Pediatrics, Federal University of São Paulo, São Paulo, Brazil;21. Department of Allergy, Hospital Clinico San Carlos, Universidad Complutense, IdISSC, Madrid, Spain

ARADyAL Research Network;22. Department of Pediatrics, Pulmonology, Allergy and Dermatology Clinic, Jagiellonian University Medical College, Krakow, Poland;23. Faculty of Public Health, Medical University-Sofia, Sofia, Bulgaria

Allergy Out-patient Department, Acibadem CityClinic, Tokuda Medical Centre, Sofia, Bulgaria;24. Service of Allergology, Complejo Hospitalario de Navarra, Pamplona, Spain;25. Clinical Allergology Department, Pomeranian Medical University in Szczecin, Szczecin, Poland;26. ARADyAL Research Network;27. Chair of Allergy, Medical University Sofia, Sofia, Bulgaria;28. Department for Allergy and Asthma, Johanniter Hospital, Treuenbrietzen, Germany;29. Paul-Ehrlich-Institut, Langen, Germany;30. Division of Allergy and Immunology, Department of Dermatology Venerology and Allergology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany

Department for Infectious Disease Epidemiology, Robert Koch-Institut, Berlin, Germany