The major cause of acne is heredity, which determines skin type. For mild acne, washing the face removes oil from the skin and keeps the pores open.
Frequent shampoos can keep oily hair from adding oil to the infected areas.
If your teen has acne on the back, he or she should scrub once or twice daily with an anti-bacterial abrasive soap and a back brush. When washing isn't enough, your teen needs to see a physician, possibly a dermatologist, who may prescribe special gels, lotions or oral medication to control the acne. Do not assume your teen will simply outgrow acne. Untreated acne can cause cysts, scars and much emotional pain. The Parenting Resource Center on the Web.