What causes acne?

The primary causes of acne are hormones, extra sebum, follicle fallout, bacteria and inflammation. Acne occurs when tiny holes on the surface of the skin, known as pores, become clogged.

At puberty, the body begins producing hormones called androgens. These hormones cause the sebaceous glands to become enlarged, which is a natural part of development. However, acne sufferers have over-stimulated sebaceous glands, which can continue for years, or even decades. Androgens may cause acne flare-ups later in life with the menstrual cycle or, occasionally, with pregnancy.

Extra sebum is produced when the sebaceous gland is stimulated by the androgens. Sebum may mix with common skin bacteria and dead skin cells as it moves up the follicle toward the surface of the skin. This may cause clogging, which, in turn, may cause acne.

The skin usually sheds dead cells within the follicle. However, when the previously described processes occur and the follicle becomes plugged, the skin cannot finish the process of renewal. This is not actually acne, but it contributes to the growth of acne bacteria.

Normal skin of all types contains the bacterium Propionibacterium acnes. These bacteria multiply rapidly in plugged follicles, causing inflammation in the follicle and surrounding skin.

Inflammation occurs when white blood cells are sent to attack the proliferating bacteria. This may, in turn, cause the skin to become red, swollen and painful. Adult women generally have a particularly strong inflammatory response, which is why women tend to be more likely than men to have acne beyond the teen years.

Acne may be aggravated by drugs containing corticosteroids, androgens or lithium. Dairy products or carbohydrate-rich foods also may aggravate acne.

Frequent cleaning of the skin is an effective treatment of acne, as is washing with benzoyl peroxide, which oxygenates skin, and dries and peels inside the pore. Contrary to popular opinion, after washing, moisturizer should be applied to acne.

Additional information about what causes acne may be found at these websites:

http://www.acne.com/

http://www.aad.org/skin-conditions/dermatology-a-to-z/acne

http://kidshealth.org/kid/health_problems/skin/acne.html

http://www.nlm.nih.gov/medlineplus/acne.html

http://www.mayoclinic.com/health/acne/DS00169

http://www.acne.org/

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001876/