Acne is a common inflammatory skin disease characterized by pimples on the face, chest, and back. It occurs when the pores of the skin become clogged with oil, dead skin cells, and/or bacteria.
Acne vulgaris, the medical term for common acne, is the most common skin disease. It affects nearly 17 million people in the United States. While acne can arise at any age, it usually begins at puberty and worsens during adolescence. Nearly 85% of people develop acne some time between the ages of 12 and 25 years old. Up to 20% of women develop mild acne. It is also found in some newborns.
The sebaceous glands lie just beneath the skin's surface. They produce sebum, an oily secretion that helps to preserve the flexibility of the hair and moisturizes the skin. These glands and the hair follicles within which they are found are called sebaceous follicles. These follicles open onto the skin through pores that allow the sebum to reach the hair shaft and the skin. In certain situations, the glands excrete excess sebum and it cannot be cleared from the pores efficiently. This happens, for instance, at puberty when increased levels of the androgen hormones cause overproduction of sebum. In addition, cells lining the follicle are shed too quickly and begin to clump together. The excess sebum combines with the dead cells and forms a plug, or comedo (also called comedones), that blocks the pore, which is not usually seen. When the follicle begins to bulge and show up as a small whitish bump mostly under the skin, it is called a whitehead. If the comedo opens up, the top surface of the plug darkens, and it is referred to as a blackhead.
Infection results when a plugged follicle is invaded by Propionibacterium acnes, a bacteria that normally lives on the skin, and possibly other microorganisms. The bacteria produce chemicals and enzymes that bring on inflammation. Pimples are the result of infected blackheads or whiteheads that rupture, releasing sebum, bacteria, dead skin, and white blood cells onto the surrounding tissues. Inflamed pimples near the skin's surface are called papules; they are red and raised, and may be quite tender to the touch. The papules may become filled with pus, and are then called pustules. If the follicle continues to enlarge rather than rupture, it forms a closed sac, called a cyst, which can be felt as a lump under the skin. Large hard swellings deep within the skin
are called nodules. Both nodules and cysts may cause pain and scarring.
Patience Paradox, The Gale Group Inc., Gale, Detroit,