Health Library


What is acne?

Acne is a disorder of the hair follicles and oil glands (sebaceous glands). The sebaceous glands secrete oils (sebum) to keep the skin moist. When the glands get clogged, it can lead to pimples and cysts.

Acne is very common. People of all races and ages have acne. In fact, most people in the U.S. between 11 and 30 years old will be affected by it. Even people in their 40s and 50s can have acne. However, acne most often begins in puberty. During puberty, the male sex hormones (androgens) increase in both boys and girls. This causes the sebaceous glands to make more oil.

Normally, the sebum produced travels through the hair follicles to the skin. However, skin cells can plug the follicles. This can block the sebum. When follicles become plugged, skin bacteria begin to grow inside the follicles. Inflammation and pimples then develop. The most common types of pimples are:

  • Whiteheads. These pimples stay under the skin's surface.
  • Blackheads. These rise to the surface of the skin. Although these pimples are black, the color is not from dirt. It's from the process of oxidation when the sebum is exposed to air. 
  • Papules. These are tender, small pink bumps.
  • Pustules. Pimples that have pus on the top and are red on the bottom of the lesion. These are characteristics of inflammatory acne. 
  • Nodules. These are hard, large, painful pimples that arise deep in the skin.
  • Cysts. Pus-filled, deep, painful pimples that often result in scars. 

The basic acne lesion is called a comedo.

What causes acne?

Rising hormone levels during puberty may cause acne. Also, acne is often inherited. Other causes of acne may include the following:

  • Hormone level changes during a woman’s menstrual cycle
  • Hormone changes during pregnancy
  • Starting or stopping birth control pills
  • Certain drugs (such as corticosteroids, lithium, and barbiturates)
  • Oil and grease from the scalp, mineral or cooking oil, and certain cosmetics
  • Diet may also play a role

Squeezing the pimples or scrubbing the skin too hard can make acne worse. Skin may also become irritated with friction or pressure from helmets, backpacks, or tight collars. Pollution or humidity can also irritate the skin.

What are the symptoms of acne?

Acne can appear as pimples without abscesses or pus-filled cysts that rupture and result in larger abscesses. It can happen anywhere on the body. However, acne most often appears in areas where there is a high concentration of sebaceous glands, including:

  • Face
  • Chest
  • Upper back
  • Shoulders
  • Neck

Acne may look like other skin conditions. Always talk with your healthcare provider for a diagnosis.

How is acne diagnosed?

Your healthcare provider can usually diagnose acne by examining your skin.

How is acne treated?

Your healthcare provider will consider your age, overall health, the severity of the acne and other factors in determining what treatment is best for you.

Treatment for acne focuses on minimizing scarring and improving appearance. Treatment for acne may include medicines you apply to your skin or medicine you take in pill form. Some of these medicines need to be prescribed by your healthcare provider. In some cases, a combination of both types of medicines may be advised.

Medicines you apply to the skin are often prescribed to treat acne. These may be in the form of a cream, gel, lotion, or solution. Examples include:

Benzoyl peroxide

Kills the bacteria


Helps stop or slow down the growth of the bacteria and reduces inflammation. Erythromycin and clindamycin are commonly used.


Stops the development of new acne lesions and encourages cell turnover, unplugging pimples


Decreases acne formation

Topical tazorotene, azelaic acid, salicylic acid, and dapsone are also commonly used.

Acne medicines you take by mouth, or oral antibiotics, are often prescribed to treat moderate to severe acne, and may include the following:

  • Doxycycline
  • Erythromycin
  • Tetracycline
  • Minocycline
  • Trimethoprim
  • Sulfamethasoxazole/trimethoprim

Spironolactone or birth control can be used by women to affect hormones to control acne.

Photodynamic therapy is a laser procedure used to control moderate to severe acne.

Isotretinoin is a prescription drug taken by mouth for severe, cystic, or inflammatory acne. It is used when other methods can’t prevent extensive scarring. Isotretinoin reduces the size of the sebaceous glands that make the skin oil. It also increases skin cell shedding, and affects the hair follicles. These effects reduce the development of acne. Isotretinoin can clear acne in the majority of people who use it. However, the drug has major side effects, including potential psychiatric side effects. It is very important to discuss this medicine with your healthcare provider.

Women who are pregnant or who are able to become pregnant must not take isotretinoin. It can cause birth defects. Isotretinoin can also cause miscarriage or premature birth.

Your healthcare provider can recommend specific steps to minimize acne scars.

Although acne often is a chronic condition, even if it lasts only during adolescence, it can leave lifelong scars. Acne scars typically look like "ice pick" pit scars or crater-like scars. Although proper treatment may help reduce scarring, several dermatological procedures may help to further reduce any acne scars, including the following:

  • Dermabrasion. This may be used to minimize small scars, minor skin surface irregularities, surgical scars, and acne scars. It involves removing the top layers of skin with an electrical machine that "abrades" the skin. As the skin heals from the procedure, the surface appears smoother and fresher.
  • Chemical peels. These are often used to reduce sun-damaged skin, irregular pigment, and superficial scars. The top layer of skin is removed with a chemical applied to the skin. By removing the top layer, the skin regenerates, often improving the skin's appearance.
  • Derma filler injections. These are injected beneath the skin to replace the body's natural collagen that has been lost. Injectable dermal fillers are generally used to treat wrinkles, scars, and facial lines.
  • Laser resurfacing. This uses high-energy light to burn away damaged skin. It may be used to reduce wrinkles and fine scars.
  • Phototherapy or blue light therapy. Phototherapy using a blue light source. It has been shown to decrease the number of acne-causing bacteria with minimal side effects, such as dry skin.  Blue light therapy does not use ultraviolet (UV) light, so it does not damage the skin as earlier types of light therapy did.
  • Pulsed light and heat energy (LHE) therapy. This type of combined light and heat therapy is believed to work by destroying acne-causing bacteria. It also shrinks the glands in the skin that make oil. The FDA has approved an LHE system that uses green light and heat pulses for treating mild to moderate acne.
  • Punch grafts. Punch grafts are small skin grafts used to replace scarred skin. A hole is punched in the skin to remove the scar. This is then replaced with unscarred skin (often from the back of the earlobe). Punch grafts can help treat deep acne scars.
  • Autologous fat transfer.  An autologous fat transfer uses fat taken from another site on your own body and injects it into your skin. The fat is placed beneath the surface of the skin to push up the depressed scars. This method is used to correct deep contour defects caused by scarring from severe acne. Because the fat may be reabsorbed into the skin over months, you may need to have it repeated.

What are the complications of acne?

Acne can leave lifelong physical scars. It can also cause self-esteem problems.

Can acne be prevented?

Acne is caused by normal hormonal changes that happen during puberty. This makes prevention of acne very difficult, or even impossible.

However, avoiding substances that can cause acne may help. This includes certain medicines (such as corticosteroids, lithium, and barbiturates), mineral or cooking oil, or certain cosmetics. Also, daily shampooing helps prevent oil and grease on the scalp from getting on your face or back. Early treatment of acne may prevent it from getting worse and causing scars.

When should I call my healthcare provider?

Acne is a common condition. If you have acne that isn't helped with home care or is severe or leaving scars, see your healthcare provider.

Key points about acne

  • Acne is a disorder of the hair follicles and sebaceous glands which become clogged, leading to pimples and cysts.
  • Acne is a common condition that usually begins during puberty because of hormonal changes.
  • Acne can be either superficial or deep.
  • If untreated, acne can cause scaring that can last a lifetime.
  • Avoiding substances that make acne worse, and early treatment of acne, can reduce or prevent acne scars.

Next steps

Tips to help you get the most from a visit to your healthcare provider: 

  • Know the reason for your visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
  • Ask if your condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if you do not take the medicine or have the test or procedure.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.