Acne is a combined term that is used to describe a number of skin conditions, like blackheads, blemishes, lumps, and whiteheads. Acne is a combined term that is used to describe a number of skin conditions, like blackheads, blemishes, lumps, and whiteheads. Teenagers and adults can have acne. Stress, hormonal activity, bacteria, steroids, and overactive glands can cause acne. Source: Free Articles from ArticlesFactory.com