Acne is a disease that affects the skin's oil glands. The little pores in the skin connect to oil glands under the skin. These glands create sebum. Sebum is an oily substance. The pores in the skin connect to the glands by a follicle. Inside the follicles, oil carries dead skin cells to the surface of the skin. When the follicle of a skin gland clogs up, a pimple grows.

Nearly 17 million people in the United States have acne. It is most common in teenagers and young adults. The reason is the hormone imbalances in the teenage years. The male hormone, testerone, is mainly responsible for acne in teenagers. Although testerone is a male hormone, it is found in females as well in a lesser amount.