1. Department of Public Health and Community Medicine, Unit of Family MedicineInstitute of Medicine, Sahlgrenska Academy, University of Gothenburg Göteborg Sweden
2. Department of Dermatology and VenereologyInstitute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg Sahlgrenska Academy Göteborg Sweden
3. Department of Dermatology and VenereologyCounty Council of Östergötland Linköping Sweden
4. Department of Clinical and Experimental MedicineLinköping University Linköping Sweden
5. Allergy CentreLinköping University Hospital Linköping Sweden
6. Department of PediatricsSahlgrenska University Hospital Göteborg Sweden