Acne Acne Acne vulgaris, or common acne, is very prevalent in adolescents and young adults because the level of testosterone and other male hormones rises in both males and females as they reach puberty. This stimulates the sebaceous glands within each hair follicle to increase production of an oily substance called sebum. Sebum generally lubricates the skin, but if there is an overproduction of oil, some may become trapped in a follicle, allowing ever-present bacteria to multiply.
Most people occasionally get a pimple somewhere on their bodies.
Acne is diagnosed if you have several such spots, usually on the face, neck or upper back, which come and go for months or years. Severely infected pimples or cystic acne may take weeks to clear up and may leave noticeable scars. Almost all males age 14-18 years have some acne. It is slightly less common in females, although many women develop pimples around the time of their period. Other exacerbating factors include exposure to grease, steroids or certain medications.