Acne is a very common skin condition identified by the presence of comedones (blackheads and whiteheads) and pus-filled spots (pustules). It usually starts during puberty. Acne ranges from a few spots on the face, neck, back and chest, which most teenagers will have at some time, to a more severe problem that may cause scarring and reduce self-confidence. For most, it tends to go away by the early to mid twenties, but it can go on for longer. Acne can also develop for the first time in people in their late twenties and beyond.

Occasionally, young children will develop blackheads and/or pustules on the cheeks or nose.