Acne | Cleveland Clinic
Typical teenager with facial acne

What is acne?

Acne is the most common skin condition that people experience. Most people develop acne to some degree during their lifetime. Though it primarily affects teenagers undergoing hormonal changes, many people will develop acne as adults. Acne might be mild (few, occasional pimples), moderate (inflammatory papules), or severe (nodules and cysts). Scarring can occur. Treatment depends on the severity of the condition.

What is the cause of acne?

Acne is primarily a hormonal condition driven by male hormones, which typically become active during the teenage years. Sensitivity to such hormones — combined with surface (skin) bacteria and lipids (fatty acids) within sebaceous (oil) glands — yields acne. Common sites for acne are the face, chest, shoulders, and back — the sites of oil glands.

The first lesion in acne is a comedone or clogged pore (whiteheads, blackheads). These can become inflamed and progress to papules and pustules (small bumps), nodules, and cysts. Larger nodules and cysts and popping of pimples often lead to scarring.

Certain conditions can aggravate acne.

  • Fluctuating hormone levels around the time of menses (menstruation)
  • Manipulating (picking/prodding) acne lesions
  • Blocking clothing and headgear, such as hats and sports helmets
  • Air pollution and certain weather conditions, especially high humidity

Last reviewed by a Cleveland Clinic medical professional on 03/22/2017.


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