1. Institut d'Optique Graduate School Rhône-Alpes; Saint-Etienne 42000 France
2. Department of Medical, Surgical and Neurological Science; Dermatology Section; University of Siena; S.Maria alle Scotte Hospital; Viale Bracci, 16, 53100, Siena Italy
3. Department of Dermatology; University Hospital of Saint Etienne; Saint-Etienne 42000 France
4. Univ Lyon; UJM-Saint-Etienne; CNRS; Institut d'Optique Graduate School; Laboratoire Hubert Curien; UMR 5516; Saint-Etienne F-42023 France