1. Evidence-Based Health Care Ltd; Edinburgh UK
2. Allergy & Respiratory Research Group; Centre for Population Health Sciences; The University of Edinburgh; Edinburgh UK
3. David Hide Asthma and Allergy Research Centre; St Mary's Hospital; Newport Isle of Wight UK
4. NIHR Southampton Respiratory Biomedical Research Unit; University of Southampton and University Hospital Southampton NHS Foundation Trust; Southampton UK
5. Human Development and Health Academic Unit; Faculty of Medicine; University of Southampton; Southampton UK
6. Padua General University Hospital; Padua Italy
7. Allergy-Center-Charité; Department of Dermatology and Allergy; Charité - Universitätsmedizin; Berlin Germany
8. University Hospital Ospedali Riuniti; Ancona Italy
9. Hospital Vall d'Hebron; Barcelona Spain
10. Department of Paediatrics; Division of Paediatric Pulmonology and Paediatric Allergy, and GRIAC Research Institute University Medical Centre Groningen; University of Groningen; Groningen the Netherlands
11. Department of Paediatrics and Child Health; University College; Cork Ireland
12. Children's Hospital; Geneva Switzerland
13. Allergy Department; Hospital Clinico San Carlos; IdISSC; Madrid Spain
14. Hans Christian Andersen Children's Hospital; Odense University Hospital; Odense Denmark
15. Department of Pediatric Allergy; Division of Asthma, Allergy & Lung Biology; King's College London; London
16. King's Health Partners; MRC & Asthma UK Centre in Allergic Mechanisms of Asthma; King's College London; London UK
17. Allergy Center Charité; University Hospital Charité; Berlin Germany
18. Department of Dermatology and Allergy; Ludwig-Maximilian University; Munich Germany
19. Immunoallergology Department; Coimbra University Hospital; Coimbra Portugal
20. Department of Pediatric Respiratory Medicine and Allergy; Emma Children's Hospital; Academic Medical Center; University of Amsterdam; Amsterdam the Netherlands
21. Division of General Internal Medicine and Primary Care; Brigham and Women's Hospital/Harvard Medical School; Boston MA USA