Blackheads, or open comedones, are common in acne. Clogged hair follicles reflect light irregularly to produce this black hue.
Review Date 10/8/2018
Updated by: Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.