1. Department of Pediatrics Reinier de Graaf Hospital Delft The Netherlands
2. Section of Allergology and Clinical Immunology, Department of Internal Medicine Erasmus Medical Center Rotterdam The Netherlands
3. Department of Pediatrics Martini Hospital Groningen The Netherlands
4. Department of Pediatrics NoordWest Hospital Group Alkmaar The Netherlands
5. Pediatrics Allergy Treatment Centre, Deventer Hospital Deventer The Netherlands
6. Department of Pediatrics Elkerliek Hospital Helmond The Netherlands
7. Department of Pediatrics Catharina Hospital Eindhoven The Netherlands