1. Department of Dermatology Rouen University Hospital Center for Autoimmune Bullous Diseases, and INSERM U1234 Normandie University Rouen France
2. Department of Dermatology Medical University of Sofia Sofia Bulgaria
3. Center for Blistering Diseases Department of Dermatology University Medical Center Groningen Groningen the Netherlands
4. Department of Dermatology Henri Mondor University Hospital, (AP‐HP) Creteil France
5. Department of Dermatology Limoges University Hospital Limoges France
6. Università degli Studi di Milano Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milan Italy
7. Department of Dermatology Hospices Civils de Lyon Lyon France
8. Department of Dermatology St. Anne’s Faculty Hospital Brno Czech Republic
9. Department of Dermatology Avicenne Hospital University Paris 13 Bobigny France
10. Department of Dermatology Amiens University Hospital Amiens France
11. Department of Dermatology Clermont‐Ferrand University Hospital Clermont‐Ferrand France
12. Section of Dermatology Department of Clinical and Experimental Medicine University of Parma Parma Italy
13. Department of Dermatology Monod General Hospital le Havre France
14. Department of Dermatology University of Lübeck Lübeck Germany
15. Lübeck Institute of Experimental Dermatology University of Lübeck Lübeck Germany
16. Department of Dermatology Orleans Hospital Orléans France
17. Department of Dermatology Hôpital la Timone Assistance Publique des Hôpitaux de Marseille Marseille France
18. Department of Dermatology Saint Louis Hospital, (AP‐HP) Paris France
19. Department of Biostatistics Rouen University Hospital Rouen France