Skip to Main Content


  • A common condition that occurs when the skin's glands become clogged with oil
  • Types include blackheads (open comedones), whiteheads (closed comedones), and painful bumps (cysts)
  • Treatments include over-the-counter and prescription topical medications as well as oral pills
  • Involves medical dermatology and pediatric dermatology


Acne is a common skin condition that occurs when the sebaceous glands, which normally excrete oil to the skin’s surface, become clogged. The resulting red bumps are what we identify as pimples. 

Other types of acne lesions known as comedones appear—they are either blackheads (open comedones) or whiteheads (closed comedones). Occasionally, acne presents as large, painful bumps (cysts) below the skin's surface.

The severity of acne can vary from person to person. The condition usually dissipates over time, but it can persist, affecting a person’s social life or becoming so severe that it causes scarring.

“Acne is very common in the teenage population, but what many people do not realize is that it can persist into adulthood and throughout adult life,” says Ilya Lim, MD, a Yale Medicine dermatologist. “There is data that acne can have significant negative impact on the quality of life and even increase the risk of depression.”

At Yale Medicine, our doctors create a personalized approach to treating acne that takes into account how the condition is affecting the patient socially and emotionally.

What are the underlying causes of acne?

Acne typically develops on the face, chest, back and shoulders, and most commonly affects teenagers, although it can develop at any point in life. Why people get acne breakouts is complicated, but it’s largely a combination of hormones, bacteria and genetics.

Teenagers are most likely to develop acne because of the changes the body goes through during puberty. As hormone (particularly testosterone) levels rise, sebaceous glands begin to create more oil to protect the skin. That increase of oil means those glands can become clogged more easily, mixing oil with dead skin cells that don’t “shed out” properly. Bacteria that lives on the skin can then become trapped and grow, leading to inflammation and, as a result, pimples. (Infants can sometimes develop acne from hormones passed on from the mother during birth.)

For some, acne can be exacerbated by the following:

    How can acne be prevented?

    There are certain lifestyle modifications that can be made to improve acne and decrease the intensity and frequency of breakouts.

    Applying topical products that are non-comedogenic or oil-free as a preventative measure can be beneficial. “However, because this is an ‘inside-out process,’” says Dr. Lim, “dietary changes and avoiding exacerbating agents are often not enough. You will still get acne if you have an underlying genetic predisposition.” Commonly suggested dietary modifications include decreasing consumption of dairy products and high glycemic index foods (refined/added sugars and refined grains).

    When should you speak to a doctor about possible acne treatment?

    If acne is negatively affecting you or someone you love, then seeking medical attention from a dermatologist is advised, even in mild cases. If scarring occurs, medical help should be sought as soon as possible to prevent disfiguring skin marks. In darker skin, acne can leave post-inflammatory dark marks (hyperpigmentation) that can take a long time to resolve and fade.

    “When I see scarring or dark marks (post-inflammatory hyperpigmentation), I usually recommend a more aggressive treatment approach,” says Dr. Lim. “The good thing is that scars and dark marks generally fade and improve over time,” says Dr. Lim, “but this can take months to years.” If the acne is causing dark marks, Dr. Lim recommends the use of a daily non-comedogenic and oil-free sunscreen to help prevent darkening of hyperpigmented spots.

    How is acne treated?

    For treating mild acne, some people may find that over-the-counter topical products work well. Those products generally contain benzoyl peroxide or salicylic acid.

    When these active ingredients aren’t effective enough, a doctor will consider a range of prescription treatment options, depending on the severity of the patient's acne:

      What makes Yale Medicine’s approach to treating acne unique?

      The doctors at Yale Medicine ensure that they have adequate time to spend with patients. For Dr. Lim, a large part of that time is spent speaking with his patients with acne to find out how the condition is affecting their quality of life. Because the Yale Medicine Dermatology team sees referrals from pediatricians, other dermatologists and specialists all over the country, they are often working with teens with moderate-to-severe acne who tend to feel that societal effect.

      “We understand the tremendous psychological and social impact acne can have and take this into account when developing a treatment plan with the patients,” Dr. Lim says. “We find out how the condition is impacting patients' lives, learn about our patients’ needs, and work together to figure out the best solution.”