1. Department of Dermatology University Hospital of Münster Münster Germany
2. Hautarztpraxis am Buddenturm Münster Germany
3. German Centre for Health Services Research in Dermatology (CVderm), Institute for Health Services Research in Dermatology and Nursing University Medical Centre Hamburg‐Eppendorf Hamburg Germany
4. Center of Chronic Pruritus University Hospital of Münster Münster Germany
5. Section Pruritus Medicine, Department of Dermatology University Hospital of Münster Münster Germany
6. Support Group “Selbsthilfe Ichthyose e. V.” Mittenwalde Germany
7. Institute of Biostatistics and Clinical Research University of Münster Münster Germany
8. Medical Center, Faculty of Medicine, Institute of Human Genetics University of Freiburg Freiburg Germany
9. Hautarztpraxis am Hohenzollernring Münster Germany
10. Medical School OWL University of Bielefeld Bielefeld Germany
11. Department of Dermatology and Allergology Helios Klinikum Berlin‐Buch, Campus of Medical School Berlin Berlin Germany