What is acne? Certainly, most of us know what it is, simply because we have had to experience it at one time or another in our lives. But, in case a definition is needed, here is a short one. Acne is a dermatological term that includes clogged pores, pimples and lumps or cysts that occur on the face, neck, chest, back, shoulders, and upper arms. Acne occurs most commonly in teenagers, but is not limited to any age group, afflicting even adults in their forties. This disease has many varieties, and although none are life threatening, the more severe cases of acne can be disfiguring, leaving permanent scars on effected areas. The physical changes in body tissue - or lesions - which acne causes are described in five ways: comedos, papule, pustule, nodule and cyst. Further, these terms denote range or severity with comedo (also known as blackheads and whiteheads) at one end and nodules or cysts at the other. As stated above, acne is most common among teenagers, affecting teens betwee...