What is acne?

Acne is a chronic disorder of the hair follicles and sebaceous glands located in the middle layer of the skin. In acne, the sebaceous glands are clogged, which leads to pimples and cysts. While a mild case of acne may resolve itself on its own, more serious cases may need intervention to stop the outbreak and prevent long-term scarring.

Acne is a common condition that affects millions of people in the U.S. It most often begins in puberty, when the male sex hormones — known as androgens — increase in both boys and girls, causing the sebaceous glands in the middle layer of skin to become more active and produce more sebum.

Acne can occur anywhere on the body but most often appears on the face, chest, upper back, shoulders and neck in the form of blackheads, whiteheads, pus-filed cysts and solid, raised bumps. Depending on the severity of the acne, it can be treated with either topical medications or oral antibiotics, or a combination of the two.

The most severe cases are treated with the oral drug isotretinoin or Accutane, which can have serious unwanted side effects, including psychiatric issues and serious consequences for women who are pregnant or planning to become pregnant.

How does acne develop?

The sebaceous glands, located in the middle layer of skin, produce oil, or sebum, which normally travels to the skin's surface via hair follicles. But when skin cells plug the follicles, blocking the oil coming from the sebaceous glands, skin bacteria (called Propionibacterium acnes, or P. acnes) begin to grow inside the follicles, causing inflammation.

Acne progresses in the following manner:

  • Incomplete blockage of the hair follicle results in blackheads (a semisolid, black plug).
  • Complete blockage of the hair follicle results in whiteheads (a semisolid, white plug).
  • Infection and irritation cause whiteheads to form.

Eventually, the plugged follicle bursts, spilling oil, skin cells and the bacteria onto the skin surface. In turn, the skin becomes irritated, and pimples or lesions begin to develop. The basic acne lesion is called a comedo.

Acne can be superficial, producing pimples without abscesses, or deep, producing inflamed pimples that push down into the skin and cause pus-filled cysts that rupture and result in larger abscesses.