1. Department of Dermato-Allergology, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
2. The Danish Twin Registry, Institute of Regional Health Services Research, University of Southern Denmark, Odense
3. Odense Patient Data Explorative Network (OPEN), Odense University Hospital, Odense, Denmark
4. Department of Clinical Immunology, Naestved Hospital, Naestved, Denmark
5. Department of Dermatology, Bispebjerg Hospital, Copenhagen, Denmark6Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark