1. Centre for Human Drug Research Zernikedreef 8 2333 CL Leiden the Netherlands
2. Department of Public Health and Primary Care Leiden University Medical Centre Albinusdreef 2 2333 ZA Leiden the Netherlands
3. DDL Diagnostic Laboratory Visseringlaan 25 2288 ER Rijswijk the Netherlands
4. Department of Medical Statistics Leiden University Medical Centre Albinusdreef 2 2333 ZA Leiden the Netherlands
5. Department of Dermatology Leiden University Medical Centre Albinusdreef 2 2333 ZA Leiden the Netherlands
6. Department of Dermatology Roosevelt Clinics Rooseveltstraat 67 2321 BL Leiden the Netherlands