Acne is the common cause of spots. Most people with acne are aged between 12 and 25 but some older and younger people are affected. Boys are more commonly affected than girls. Acne usually affects the face but may also affect the back, neck and chest.
The severity can range from mild to severe. About 8 in 10 teenagers develop some degree of acne. Often it is mild. However, it is estimated that about 3 in 10 teenagers have acne bad enough to need treatment to prevent scarring. Untreated acne usually lasts about 4-5 years before settling. However, it can last for many years in some cases.