1. Department of (Pediatric) Dermatology and Allergology; University Medical Center Utrecht; Utrecht the Netherlands
2. High Altitude Clinic Merem Dutch Asthma Center Davos; Davos Switzerland
3. Department of Dermatology; Leiden University Medical Center; Leiden The Netherlands
4. Department of Pediatric Dermatology; Sophia Children's Hospital; Erasmus MC University Medical Center Rotterdam; Rotterdam the Netherlands