1. Dermatology Service, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
2. Hospital Universitario Virgen del Rocío, Seville, Spain
3. Department of Clinical Epidemiology, CIM-Caiber-IIb Sant Pau, Barcelona, Spain
4. Nowwith Dermatology Service, Hospital Sant Joan de Déu, Esplugues de Llobregat, Spain