Acne vulgaris is a skin disorder that plagues most teenagers and young adults. It starts in puberty and can persist into young adult life. Some 80 percent of us develop the pimples and bumps of acne vulgaris some time or another while we're growing up. In most cases, the pimples (often referred to as zits) and their variants—blackheads, whiteheads, pustules, and cysts—as a rule clear up by the mid to late twenties, but they can last longer. They are not usually severe, but can have a serious impact on physical or emotional health when they recur and persist in large numbers on the face, the shoulders, the neck, and the upper back.