[1] Univ Cologne, Klin & Poliklin Dermatol & Venerol, D-50937 Cologne, Germany
[2] Univ Klinikum Essen, Klin Dermatol Venerol & Allergol, D-45122 Essen, Germany
[3] Ernst Moritz Arndt Univ Greifswald, Klin & Poliklin Hautkrankheiten, D-17475 Greifswald, Germany