Acne vulgaris, known simply as acne, is among the most common skin diseases especially during adolescence. It can take many different forms including blackheads or whiteheads, pimples and pustules, or scaly red areas, all varying in size, shape, number and concentration. Acne may appear in outbreaks of differing severity for different lengths of time. Scarring may result from acne. Although hormones are often somewhat responsible, as with adolescents, levels of stress and certain bacteria as well as the consumption of certain foods also may play a role. There are also genetic factors at work. Acne is considered unsightly; acne and acne scarring may cause significant reduction in quality of life, depending on the individual patient.