Acne is a the most common condition affecting around 17 million people in the United States. Acne can range from very few mild comedonal lesions to large nodules and scarring cysts. Acne can be found on the face, chest, back, shoulders, and less frequently on the abdomen. It is typically considered a problem of the teenage years, but younger and older patients can also be affected by acne. It is caused by the overproduction of sebum. Sebum is an oily substance that forms in glands just under the surface of the skin called sebaceous glands. The glands are connected to hair follicles that allow the sebum, or oil, to empty onto the skin through a pore to moisturize the skin. When hair follicles become blocked by dead skin, sebum or bacteria, acne may result.