1. Department of Dermatology‐Center of Paediatric Dermatology Sophia Children's Hospital Erasmus MC University Medical Center Rotterdam Rotterdam The Netherlands
2. Department of Dermatology and Allergology University Medical Center Utrecht The Netherlands
3. Dutch Asthma Center Davos Davos Switzerland
4. Swiss Institute of Allergy and Asthma Research (SIAF) University of Zürich Davos Switzerland
5. Microbiology and Systems Biology TNO Zeist The Netherlands