This is a condition presenting unsightly red and swollen follicles that we call pimples. Acne affects ~85% of the population at some time in their life, including adults. Most teens get the type of acne called acne vulgaris, which can appear on face, neck, shoulders, back and chest (these are the locations where most sebum-secreting sebaceous glands are found). Appearing on the face as it does, it obviously causes its owner significant psychological stress.
Acne can be a chronic problem - sometimes lasting several years
Occurs when comedones rupture, spreading bacteria with associated inflammation: