Acne is a chronic, inflammatory skin condition that causes spots and pimples, especially on the face, shoulders, back, neck, chest, and upper arms.

Whiteheads, blackheads, pimples, cysts, and nodules are all types of acne.

It is the most common skin condition in the United States, affecting up to 50 million Americans yearly.

It commonly occurs during puberty, when the sebaceous glands activate, but it can occur at any age. It is not dangerous, but it can leave skin scars.

The glands produce oil and are stimulated by male hormones produced by the adrenal glands in both males and females.

At least 85 percent of people in the U.S. experience acne between the ages of 12 and 24 years.

Fast facts on acne

Here are some facts about acne. More detail is in the main article.

Acne is a skin disease involving the oil glands at the base of hair follicles.

It affects 3 in every 4 people aged 11 to 30 years.

It is not dangerous, but it can leave skin scars.

Treatment depends on how severe and persistent it is.

Risk factors include genetics, the menstrual cycle, anxiety and stress, hot and humid climates, using oil-based makeup, and squeezing pimples.