There's a reason it's called "common acne" -- nearly everyone suffers from a pimple outbreak at some point in life.
It starts when greasy secretions from the skin's sebaceous glands (oil glands) plug the tiny openings for hair follicles (plugged pores). If the openings are large, the clogs take the form of blackheads: small, flat spots with dark centers. If the openings stay small, the clogs take the form of whiteheads: small, flesh-colored bumps. Both types of plugged pores can develop into swollen, tender inflammations or pimples or deeper lumps or nodules. Nodules associated with severe cases of acne (cystic acne) are firm swellings below the skin's surface that become inflamed, tender, and sometimes infected.
Although acne remains largely a curse of adolescence, about 20% of all cases occur in adults. Acne commonly starts during puberty between the ages of 10 and 13 and tends to be worse in people with oily skin. Teenage acne usually lasts for five to 10 years, normally going away during the early 20s. It occurs in both sexes, although teenage boys tend to have the most severe cases. Women are more likely than men to have mild to moderate forms into their 30s and beyond.
Acne lesions are most common on the face, but they can also occur on the neck, chest, back, shoulders, and upper arms.
Contrary to popular belief, acne isn't caused by a harmful diet, poor hygiene, or an uncontrolled sex drive. The simple truth is that heredity and hormones are behind most forms of acne. Swearing off chocolate or scrubbing your face 10 times a day won't change your predisposition to this unsightly, sometimes painful, and often embarrassing skin problem.
What Causes Acne?
The cause of acne is not fully understood. Though stress can aggravate acne, it clearly does not cause it.
Hormones. Common acne in teenagers starts with an increase in hormone production. During puberty, both boys and girls produce high levels of androgens, the male sex hormones that include testosterone. Testosterone signals the body to make more sebum, the oil produced in the skin's oil glands.