Blackheads, or open comedones, are common in acne. Clogged hair follicles reflect light irregularly to produce this black hue.
Review Date 8/14/2021
Updated by: Elika Hoss, MD, Senior Associate Consultant, Mayo Clinic, Scottsdale, AZ. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.