A Egeberg1, A Nast2. 1. Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen, 2900, Hellerup, Denmark. 2. Division of Evidence Based Medicine (dEBM), Department of Dermatology, Venerology und Allergy, Charité - Universitätsmedizin Berlin, D-10117, Berlin, Germany.