First evidence of bacterial biofilms in the anaerobe part of scalp hair follicles: a pilot comparative study in folliculitis decalvans

Abstract

The cause of folliculitis decalvans (FD) remains unknown. We hypothesized that a bacterial biofilm could be involved in its pathogenesis. To assess the presence or not of a bacterial biofilm in the hair roots of the scalp in FD. Hairs plucked from four patients and three controls were examined by field emission scanning electron microscopy (FESEM) and confocal laser scanning microscopy (CLSM). Bacterial communities organized as biofilms were observed both by FESEM and CLSM in the under infundibular part of hair follicles in all patients and in two of the three controls. In patients and controls, these biofilms were formed exclusively of bacilli of comparable shapes. This pilot study provides the first evidence of the presence of bacterial biofilms in the infra infundibular part of human scalp hair follicles. These biofilms were detected both in FD patients and controls, suggesting their ubiquity as a commensal biofilm with a possible pathogenic shift in FD.