1. Department of Dermatology, Venerology and Allergology; Universität Leipzig; Leipzig Germany
2. Clinical Trial Centre Leipzig (ZKS); Universität Leipzig; Leipzig Germany
3. Allergy Unit; Department of Dermatology; University Hospital Zürich and Centre of Dermatology and Allergology; Luzerner Kantonsspital; Luzern Germany
4. Allergy Center Charité; Department of Dermatology, Venerology and Allergology; Charité - Universitätsmedizin Berlin; Berlin Germany
5. Department of Dermatology and Allergology; MH Hannover; Hannover Germany
6. Division of Clinical & Molecular Allergology Research Center Borstel; Airway Research Center North (ARCN) and Member of the German Center for Lung Research (DZL); Borstel Germany
7. Interdisciplinary Allergy Outpatient Clinic; Department of Internal Medicine; University of Lübeck; Lübeck Germany
8. Department of Dermatology; Universität Tübingen; Tübingen Germany
9. Department of Dermatology and Allergology; Technical University Munich; Munich Germany
10. Department of Dermatology; Medical Faculty Carl Gustav Carus; TU Dresden; Dresden Germany
11. Center for Evidence-based Healthcare; Medical Faculty Carl Gustav Carus; TU Dresden; Dresden Germany
12. Department of Dermatology; Universität Münster; Münster Germany
13. Department of Dermatology; Elbekliniken Buxtehude; Buxtehude Germany
14. Allergy- and Asthma Centre Westend; Berlin Germany
15. Day care clinic for Allergy and Dermatology; Kiel Germany
16. Department of Dermatology and Allergology; Ludwig-Maximilian University; Munich Germany
17. Department of Dermatology; University Medical Center; Johannes Gutenberg-University; Mainz Germany
18. Department of Dermatology; Ruprecht-Karls-Universität Heidelberg; Heidelberg Germany
19. Division of Allergology; Paul-Ehrlich-Institut; Langen Germany