Acne is a common skin condition that happens when hair follicles under the skin become clogged. Sebum—oil that helps keep skin from drying out—and dead skin cells plug the pores, which leads to outbreaks of lesions, commonly called pimples or zits. Most often, the outbreaks occur on the face but can also appear on the back, chest, and shoulders.

Acne is an inflammatory disorder of the skin, which has sebaceous (oil) glands that connects to the hair follicle, which contains a fine hair. In healthy skin, the sebaceous glands make sebum that empties onto the skin surface through the pore, which is an opening in the follicle. Keratinocytes, a type of skin cell, line the follicle.  Normally as the body sheds skin cells, the keratinocytes rise to the surface of the skin. When someone has acne, the hair, sebum, and keratinocytes stick together inside the pore. This prevents the keratinocytes from shedding and keeps the sebum from reaching the surface of the skin. The mixture of oil and cells allows bacteria that normally live on the skin to grow in the plugged follicles and cause inflammation—swelling, redness, heat, and pain. When the wall of the plugged follicle breaks down, it spills the bacteria, skin cells, and sebum into nearby skin, creating lesions or pimples.

For most people, acne tends to go away by the time they reach their thirties, but some people in their forties and fifties continue to have this skin problem.

There are many myths about what causes acne. Some people blame foods for their outbreaks. Some think that dirty skin causes it. But there’s little evidence that either has much effect on most people’s acne.

People of all races and ages get acne. About 4 of every 5 people between the ages of 11 and 30 have outbreaks at some point. It’s most common in adolescents and young adults. Although acne is usually not a serious health threat, it can be upsetting, and severe acne can lead to permanent scarring. Fortunately, for most people, acne tends to go away by the time they reach their 30s.

Acne begins in the skin’s oil glands. The oils travel up a canal called a follicle, which also contains a hair. The oils empty onto the skin surface through the follicle’s opening, or pore.

The hair, oil and cells that line the narrow follicle can form a plug and block the pore, preventing oil from reaching the skin’s surface. This mix of oil and cells allows bacteria that normally live on the skin to grow in plugged follicles. Your body’s defense system then moves to attack the bacteria and the area gets inflamed.

If the plugged follicle stays beneath the skin, you get a white bump called a whitehead. If it reaches the surface of the skin and opens up, you get a blackhead. It’s not because of dirt; the oil becomes black on the skin’s surface when it’s exposed to air. Both whiteheads and blackheads may stay in the skin for a long time. Eventually, the wall of the plugged follicle can break down, leading to pimples, or zits.

One important factor in acne is an increase in certain hormones during puberty. These hormones cause the oil glands to enlarge and make more oil. Hormone changes related to pregnancy or starting or stopping birth control pills can also cause acne.

Studies suggest that you can inherit a tendency to develop acne from your parents, so genes likely play some role. Stress doesn’t cause acne, but research has found that for people who have acne, stress can make it worse.

Certain drugs are also known to cause acne. Greasy cosmetics, for example, can alter the cells of the follicles and make them stick together, producing a plug. If you have acne, try oil-free cosmetics. Choose products labeled noncomedogenic (meaning they don’t promote the formation of closed pores).

If you have acne, don’t rub or touch your pimples. Squeezing, pinching or picking at them can lead to scars or dark blotches. Gently wash your face with a mild cleanser twice a day—and after heavy exercise. Don’t use strong soaps or rough scrub pads; they may make the problem worse. It’s also important to shampoo your hair regularly. If you have oily hair, you may want to wash it every day.

Several over-the-counter medicines can treat mild acne. It may take up to 8 weeks before you notice an improvement. For more severe acne, talk to your doctor about the options.

Researchers continue to work on developing new drugs to treat acne. They’re also trying to better understand the causes of acne so they can explore new remedies. In the meantime, there are several available treatments that may help.

Acne Flare-ups

The exact cause of acne is unknown, but certain factors can cause it to flare. They include:

• Changing hormone levels in adolescent girls—and adult women 2 to 7 days before their menstrual period starts
• Oil from skin products (moisturizers or cosmetics) or grease in the work environment (for example, a kitchen with fry vats)
• Pressure from sports helmets or equipment, backpacks, tight collars or tight sports uniforms
• Skin irritants, such as pollution and high humidity
• Squeezing or picking at blemishes
• Hard scrubbing of the skin
• Stress

Rosacea (ro-ZAY-she-ah) is a common skin problem often called "adult acne." Faired skinned and menopausal women are more likely to have rosacea. Rosacea also seems to run in families. It causes redness in the center parts of the face and pimples. Blood vessels under the skin of the face may enlarge and show through the skin as small red lines. The skin may be swollen and feel warm.

Women with rosacea don't have the same lesions as seen with common acne. They may have flushing of the face, when they are hot, drink alcohol or hot drinks, or eat spicy foods. This flushing causes the face to appear red. In the most severe form, this redness does not go away. The eyes may become swollen and nodules in the skin may be painful.

You can help keep rosacea under control by keeping a record of things that cause it to flare up. Try to avoid or limit these triggers as much as you can. Antibiotic lotions or gels can also help. Sometimes, you may need to take antibiotic pills. Your dermatologist may treat you with laser surgery. If you think you have rosacea, talk with your doctor about these treatments.

Acne causes several types of lesions, or pimples. Doctors refer to enlarged or plugged hair follicles as comedones. Types of acne include:

• Whiteheads: Plugged hair follicles that stay beneath the skin and produce a white bump.
• Blackheads: Plugged follicles that reach the surface of the skin and open up. They look black on the skin surface because the air discolors the sebum, not because they are dirty.
• Papules: Inflamed lesions that usually appear as small, pink bumps on the skin and can be tender to the touch.
• Pustules or pimples: Papules topped by white or yellow pus-filled lesions that may be red at the base.
• Nodules: Large, painful solid lesions that are lodged deep within the skin.
• Severe nodular acne (sometimes called cystic acne): Deep, painful, pus-filled lesions.

People of all races and ages get acne, but it is most common in teens and young adults. When acne appears during the teenage years, it is more common in males. Acne can continue into adulthood, and when it does, it is more common in women.

Doctors and researchers believe that one or more of the following can lead to the development of acne:

• Excess or high production of oil in the pore.
• Buildup of dead skin cells in the pore.
• Growth of bacteria in the pore.

The following factors may increase your risk for developing acne:

• Hormones. An increase in androgens, which are male sex hormones, may lead to acne. These increase in both boys and girls normally during puberty and cause the sebaceous glands to enlarge and make more sebum. Hormonal changes related to pregnancy can also cause acne. 
• Family history. Researchers believe that you may be more likely to get acne if your parents had acne.
• Medications. Certain medications, such as medications that contain hormones, corticosteroids, and lithium, can cause acne.
• Age. People of all ages can get acne, but it is more common in teens.

The following do not cause acne, but may make it worse.

• Diet. Some studies show that eating certain foods may make acne worse. Researchers are continuing to study the role of diet as a cause of acne.
• Stress.
• Pressure from sports helmets, tight clothes, or backpacks.
• Environmental irritants, such as pollution and high humidity.
• Squeezing or picking at blemishes.
• Scrubbing your skin too hard.

To diagnose acne, health care providers may:

• Ask about your family history, and, for girls or women, ask about their menstrual cycles.
• Ask you about your symptoms, including how long you have had acne.
• Ask what medications you are currently taking or recently stopped.
• Examine your skin to help determine the type of acne lesion.
• Order lab work to determine if another condition or medical disorder is causing the acne.

The goals of treatment are to help heal existing lesions, stop new lesions from forming, and prevent scarring. Medications can help stop some of the causes of acne from developing, such as abnormal clumping of cells in the follicles, high sebum levels, bacteria, and inflammation. Your doctor may recommend over-the-counter or prescription medications to take by mouth or apply to the skin.

Topical medications, which you apply to the skin, include:

• Over-the-counter products, such as benzoyl peroxide, which kills bacteria and may decrease the production of sebum.
• Antibiotics, which are usually used with other topical medications.
• Retinoids, which come from vitamin A and can help treat lesions and reduce inflammation. They can also help prevent the formation of acne and help with scarring.
• Salicylic acid, which helps break down blackheads and whiteheads and also helps reduce the shedding of cells lining the hair follicles.
• Sulfur, which helps break down blackheads and whiteheads.

Topical medicines come in many forms, including gels, lotions, creams, soaps, and pads. In some people, topical medicines may cause side effects such as skin irritation, burning, or redness. Talk to your doctor about any side effects that you experience.  

For some people, the doctor may prescribe oral medications, such as:

• Antibiotics, which help slow or stop the growth of bacteria and reduce inflammation. Doctors usually prescribe antibiotics for moderate to severe acne, such as severe nodular acne (also called cystic acne).
• Isotretinoin, an oral retinoid,  which works through the blood stream to help treat acne and open up the pore.  This allows other medications, such as antibiotics, to enter the follicles and treat the acne. Similar to topical retinoids, taking the medication by mouth can also help prevent the formation of acne and help with scarring.
• Hormone therapy, used primarily in women, which helps stop the effects of androgens on the sebaceous gland.
• Corticosteroids, which help lower inflammation in severe acne, including severe nodular acne. 

Some people who have severe acne or acne scarring that does not respond to topical or oral medications may need additional treatments, such as:

• Laser and other light therapies. However, researchers are still studying the best types of light and the amount needed to treat acne.
• Injecting corticosteroids directly into affected areas of your skin.
• Superficial chemical peels that a doctor recommends and applies to the area.
• Filling acne scars with a substance to improve their appearance.
• Treating acne scars with tiny needles to help induce healing. 
• Surgical procedures to help treat and repair scarring.

In addition to experiencing significant scarring, people of color can develop skin discoloration after acne heals. Your doctor can suggest a treatment approach that can fade existing dark spots. Using sunscreen when outdoors is especially important to help treat  and prevent dark spots.

The following health care providers may diagnose and treat acne:

• Dermatologists, who specialize in conditions of the skin, hair, and nails.
• Primary health care providers, including family doctors, internists, or pediatricians. 

Zits. Pimples. Spots. Whatever you call it, acne can cause discomfort and embarrassment. This skin condition affects most people at some point during their lives. About 4 out of every 5 people experience acne outbreaks between the ages of 11 and 30.

Acne starts in the skin’s oil glands. The hair on our bodies comes out through canals from these glands called follicles. Oil glands make oils that emerge to the skin’s surface through the follicles’ openings, or pores, along with the hairs.

Sometimes hair, oil, and dead skin cells come together to plug a follicle. The plugged pore provides the right conditions for bacteria that normally live on the skin to thrive. When the body’s immune system attacks the bacteria, pain and swelling can result. That’s how a pimple forms.

Doctors don’t know why only some people get acne. They do know what raises the risk for acne. Increases in certain hormones can cause oil glands to get bigger and make more oil. These hormone levels go up during puberty. Because of this, acne is most common in adolescents and young adults. Hormone changes caused by pregnancy or by starting or stopping birth control pills can also trigger acne.

But people of all ages can get acne. For most, acne goes away by the time they reach their 30s. However, some people in their 30s, 40s, and 50s still get acne. Although acne is usually not a serious health threat, it can be upsetting, and severe acne can lead to permanent scarring.

There are things you can do to prevent acne, explains Dr. Edward Cowen, a skin specialist at NIH. He recommends that people with acne avoid skin products that contain petrolatum, a type of oil. Instead, he says, look for creams and lotions labeled “noncomedogenic.” These are less likely to clog pores. A lot of people think certain foods can cause acne breakouts. However, Cowen explains, research has not been able to confirm this in most cases. See the Wise Choices box for other tips.

While there are plenty of home remedies for acne, Cowen says, it’s better to start with proven over-the-counter treatments for mild acne. These products can contain benzoyl peroxide, resorcinol, salicylic acid, or sulfur.

People with severe acne should discuss prescription drug options with a doctor, he adds. These include antibiotics to kill bacteria or drugs called retinoids, which can be given as a topical to apply to the skin or as an oral medication.

NIH-funded scientists are conducting research to better understand why acne develops and to find better ways to treat the condition.

Fight Acne Flare-Ups

These good habits can help reduce acne:

• Be gentle. Avoid scrubbing hard when washing your face.
• Hands off. Resist the temptation to squeeze or pick at pimples.
• Avoid oily skin products. Choose lotions and make-up labeled “noncomedogenic.” These are less likely to clog your pores.
• Wash your hair. If you have oily hair, washing it every day can reduce oil on the skin.
• Loosen up. Avoid pressure from tight-fitting clothing, sports equipment, or backpack straps, which can irritate the skin.

If you have acne, the following recommendations may help you in taking care of your skin.

• Clean your skin gently. Use a mild cleanser in the morning, in the evening, and after heavy exercise. Try to avoid using strong soaps, astringents, or rough scrub pads. Rinse your skin with lukewarm water.
• Shampoo your hair regularly, especially if you have oily hair.
• Avoid rubbing and touching skin lesions. Squeezing or picking blemishes can cause scars or dark blotches to develop.
• Shave carefully. Make sure the blade is sharp, and soften the hair with soap and water before applying shaving cream. Shave gently and only when necessary to reduce the risk of nicking blemishes.
• Use sunscreen, and avoid sunburn and suntan. Many of the medicines used to treat acne can make you more prone to sunburn.
• Choose cosmetics carefully. All cosmetics and hair care products should be oil free. Choose products labeled noncomedogenic, which means they do not clog pores. In some people, however, even these products may make acne worse.

Acne can cause embarrassment or make you feel shy or anxious. If you have any of these feelings, talk to your doctor.