[1] Univ Cologne, Med Fak, Kerpener Str 62, D-50937 Cologne, Germany
[2] Univ Cologne, Uniklin Koln, Klin Dermatol & Venerol, Kerpener Str 62, D-50937 Cologne, Germany
[3] Univ Witten Herdecke, HELIOS St Elisabeth Klin Oberhausen, Klin Dermatol Venerol & Allergol, Oberhausen, Germany