Acne

What is acne?
Acne is a disorder of the hair follicles and sebaceous glands. With acne, the sebaceous glands are clogged, which leads to pimples and cysts.
Acne is very common - nearly 17 million people in the US are affected by this condition. Acne most often begins in puberty. During puberty, the male sex hormones (androgens) increase in both boys and girls, causing the sebaceous glands to become more active - resulting in increased production of sebum.

How does acne develop?
The sebaceous glands produce oil (sebum) which normally travels via hair follicles to the skin surface. However, skin cells can plug the follicles, blocking the oil coming from the sebaceous glands. When follicles become plugged, skin bacteria (called Propionibacterium acnes, or P. acnes) begin to grow inside the follicles, causing inflammation. Acne progresses in the following manner:
Incomplete blockage of the hair follicle results in blackheads (a semisolid, black plug).
Complete blockage of the hair follicle results in whiteheads (a semisolid, white plug).
Infection and irritation cause whiteheads to form.
Eventually, the plugged follicle bursts, spilling oil, skin cells, and the bacteria onto the skin surface. In turn, the skin becomes irritated and pimples or lesions begin to develop. The basic acne lesion is called a comedo.
Acne can be superficial (pimples without abscesses) or deep (when the inflamed pimples push down into the skin, causing pus-filled cysts that rupture and result in larger abscesses).