Definition: An inflamed acne lesion presenting as a hard, painful lump under the skin. Nodules occur when there is a deep break in the follicle wall and contaminated debris empties into the dermis, infecting adjoining follicles.
By Angela Palmer, About.com
Updated: June 11, 2009
About.com Health's Disease and Condition content is reviewed by the Medical Review Board
Nodular Acne
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