1. Institute for Health Services Research in Dermatology and Nursing (IVDP), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany.
2. A+ Videoclinic GmbH, Munich, Germany.
3. Institute of Primary Care, University Hospital of Zurich, Zurich, Switzerland.
4. Department of General Practice and Primary Care, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany.