Definition: A type of acne lesion, a comedo occurs when a plug of oil and dead skin cells becomes trapped within the hair follicle. There are many different types of comedones.
Also Known As: Comedones (plural), blackhead, pore blockage, impaction.
Comedo
By Angela Palmer, About.com
Updated: June 17, 2009
About.com Health's Disease and Condition content is reviewed by the Medical Review Board
Comedones
Photo © A.D.A.M.
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