Acne FAQ • What Is Acne? • How Does Acne Develop? • What Causes Acne? • Factors That Can Make Acne Worse • How Is Acne Treated? • Treatment for Blackheads, Whiteheads, and Mild Inflammatory Acne • Treatment for Moderate to Severe Inflammatory Acne • Treatment for Severe Nodular or Cystic Acne • Other Treatments for Acne • How Should People With Acne Care for Their Skin? • What Research Is Being Done on Acne? • Why Acne Forms, and How Accutane Knocks It Out • Where Can People Find More Information on Acne?

• Changing hormone levels in adolescent girls and adult women 2 to 7 days before their menstrual period starts
• Friction caused by leaning on or rubbing the skin
• Pressure from bike helmets, backpacks, or tight collars
• Environmental irritants, such as pollution and high humidity
• Squeezing or picking at blemishes
• Hard scrubbing of the skin.

There are many myths about what causes acne. Chocolate and greasy foods are often blamed, but foods seem to have little effect on the development and course of acne in most people. Another common myth is that dirty skin causes acne; however, blackheads and other acne lesions are not caused by dirt. Finally, stress does not cause acne.

Source: National Institute of Arthritis and Musculoskeletal and Skin Diseases.