1 Departments of Dermatology, Venereology, Allergology and Immunology, Dessau Medical Center, Brandenburg Medical School Theodor Fontane, Dessau, Germany.
2 European Hidradenitis Suppurativa Foundation e.V., Dessau, Germany.
3 Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Wroclaw, Poland.
4 Department of Dermatology, Zealand University Hospital, Roskilde; Health Sciences Faculty, University of Copenhagen, Denmark.