Comedo, a clogged hair follicle, is one of the predisposing factors of acne. Comedo formation has been known to result from obstruction of the follicular orifice by hyperkeratosis, followed by sebum coagulation with corneocytes in the follicle [ [1] Goh C. Cheng C. Agak G. Zaenglein A.L. Graber E.M. Thiboutot D.M. et al. Acne vulgaris.

in: Fitzpatrick’s Dermatology. McGraw-Hill Inc., US2019: 1391-1418

]. However, since this process cannot sufficiently explain the formation of open comedo and microcomedo, where the follicular orifice is open, the detailed mechanism of comedo formation remains to be elucidated. In this study, we performed immunological and histological analyses using the follicular plug of the human nose and excised human skin, including clogged hair follicles, to investigate the mechanism of comedo formation.