Acne

This fact sheet contains general information about acne. It describes what acne is and how it develops, the causes of acne, and the treatment options for various forms of acne. Information is also provided on caring for the skin. If you have further questions after reading this fact sheet, you may wish to discuss them with your doctor.

• What Is Acne?
• How Does Acne Develop?
• What Causes Acne?
• Who Gets Acne?
• How Is Acne Treated?
• Treatment for Blackheads, Whiteheads, and Mild Inflammatory Acne
• Treatment for Moderate to Severe Inflammatory Acne
• Treatment for Severe Nodular or Cystic Acne
• Treatments for Hormonally Influenced Acne
• Other Treatments for Acne
• How Should People With Acne Care for Their Skin?
• What Research Is Being Done on Acne?
• Where Can People Find More Information on Acne?
• Acknowledgments

Acne is a disorder of the skin’s oil glands (sebaceous glands) that results in plugged pores and outbreaks of lesions commonly called pimples or zits. Acne lesions usually occur on the face, neck, back, chest, and shoulders. Nearly 17 million people in the United States have acne, making it the most common skin disease. Although acne is not a serious health threat, severe acne can lead to disfiguring, permanent scarring, which can be upsetting for people who suffer from the disorder.

How Does Acne Develop?

Doctors describe acne as a disease of the pilosebaceous units. Found over most of the body, pilosebaceous units consist of a sebaceous (oil) gland connected to a hair-containing canal called a follicle (see figure 1). These units are largest and most numerous on the face, upper back, and chest—areas where acne tends to occur. The sebaceous glands make an oily substance called sebum that normally empties onto the skin surface through the opening of the follicle.

Figure 1.

Normal Pilosebaceous Unit

Acne is believed to result from a change in the inner lining of the follicle that prevents the sebum from passing through. For reasons not understood, cells from the lining of the follicle are shed too fast and clump together. The clumped cells plug up the follicle’s opening so sebum cannot reach the surface of the skin. The mixture of oil and cells causes bacteria that normally live on the skin, called Propionibacterium acnes (P. acnes), to grow in the plugged follicles. These bacteria produce chemicals and enzymes that can cause inflammation. (Inflammation is a characteristic reaction of tissues to disease or injury and is marked by four signs: swelling, redness, heat, and pain.) When the plugged follicle can no longer hold its contents, it bursts and spills everything onto the nearby skin—sebum, shed skin cells, and bacteria. Lesions or pimples develop as a result of the skin’s being irritated.

People with acne frequently have a variety of lesions, some of which are shown in figures 2, 3, and 4. The basic acne lesion, called the comedo (kom´-e-do) or comedone, is simply an enlarged hair follicle plugged with oil and bacteria. This lesion is often referred to as a microcomedo because it cannot be seen by the naked eye. If the plugged follicle, or comedo, stays beneath the skin, it is called a closed comedo or whitehead. Whiteheads usually appear on the skin surface as small, whitish bumps. A comedo that reaches the surface of the skin and opens up is called a blackhead because it looks black on the skin’s surface. This black discoloration is not due to dirt. Both whiteheads and blackheads may stay in the skin for a long time.

Other troublesome acne lesions can develop, including the following:

• Papules—inflamed lesions that usually appear as small, pink bumps on the skin and can be tender to the touch.
  
  
• Pustules (pimples)—inflamed, pus-filled lesions that can be red at the base.
  
  
• Nodules—large, painful, solid lesions that are lodged deep within the skin.
  
  
• Cysts—deep, inflamed, pus-filled lesions that can cause pain and scarring.
  
  

Figure 2. Microcomedo
Figure 3. Open Comedo (Blackhead)		Figure 4. Closed Comedo (Whitehead)

What Causes Acne?

The exact cause of acne is unknown, but doctors believe it results from several related factors. One important factor is rising hormone levels. These hormones, called androgens (male sex hormones), increase in both boys and girls during puberty and can cause the sebaceous glands to enlarge and make more sebum. Another factor is heredity or genetics. Researchers believe that the tendency to develop acne can be inherited from parents. For example, studies have shown that many school-age boys with acne have a family history of the disorder.

Factors That Can Contribute to Acne or Make It Worse

Several factors can contribute to the cause of acne or make it worse. Changing hormone levels in girls and women may cause a flare in their acne 2 to 7 days before their menstrual period starts. Hormonal changes related to pregnancy or starting or stopping birth control pills can also cause acne. Stress, particularly severe or prolonged emotional tension, may aggravate the disorder.

In addition, certain drugs, including androgens, lithium, and barbiturates, are known to cause acne. Greasy cosmetics may alter the cells of the follicles and make them stick together. Friction caused by leaning on or rubbing the skin or the pressure from bike helmets, backpacks, or tight collars can contribute to or worsen acne. Also, environmental irritants (such as pollution and high humidity), squeezing or picking at blemishes, and hard scrubbing of the skin can make acne worse.

Myths About the Causes of Acne

There are many myths about what causes acne. Chocolate and greasy foods are often blamed, but research has shown that foods seem to have little effect on the development and course of acne in most people. Another common myth is that dirty skin causes acne; however, blackheads and other acne lesions are not caused by dirt.

Who Gets Acne?

People of all ages get acne, but it is most common in adolescents. Nearly 85 percent of adolescents and young adults between the ages of 12 and 24 develop the disorder. People of all races can have acne, but it is more common among Caucasians. For most people, acne tends to go away by the time they reach their thirties; however, some people in their forties and fifties continue to have the disorder.

How Is Acne Treated?

By the time many people consult a doctor for their acne, they usually have tried a drawerful of over-the-counter (OTC) medications. Acne is often treated by a dermatologist, a doctor who specializes in diseases and disorders of the skin. Dermatologists treat all kinds of acne, particularly severe cases. Doctors who are general or family practitioners, pediatricians, or internists may treat patients with milder cases of acne.

The main goal of acne treatment is to prevent scarring. Additional goals are to reduce the number of painful lesions and to minimize the psychological stress and embarrassment caused by this disease. Doctors often use drug therapy as the first choice for treating acne. Drug therapy is aimed at reducing several problems that play a part in causing acne: abnormal clumping of cells in the follicles, increased oil production, the bacterium P. acnes, and inflammation. Depending on the severity of the person’s acne, the doctor will recommend one of several OTC or prescription topical medications (medication applied to the skin) or a prescription systemic medication (medication taken by mouth). The doctor may suggest using more than one topical medication or using both an oral medication and a topical medication at the same time.

*Brand names included in this fact sheet are provided as examples only, and their inclusion does not mean that these products are endorsed by the National Institutes of Health or any other Government agency. Also, if a particular brand name is not mentioned, this does not mean or imply that the product is unsatisfactory.

Treatment for Blackheads, Whiteheads, and Mild Inflammatory Acne

Doctors usually recommend an OTC or prescription topical medication for people with blackheads, whiteheads, and mild inflammatory acne. Depending on the type of medication, a topical drug is applied directly to the acne lesions or to the entire area of skin affected. The medication helps limit the formation of new blackheads and whiteheads and decrease inflammation.

Treatment for Moderate to Severe Inflammatory Acne

Patients with moderate to severe inflammatory acne may be treated with an OTC or prescription topical medication, a prescription oral medication, or a combination of these.

Topical OTC Medications

Benzoyl peroxide, resorcinol, salicylic acid, and sulfur are the most common topical OTC medications used to treat acne. Each works a little differently. Benzoyl peroxide is best at killing P. acnes and may reduce oil production. Resorcinol, salicylic acid, and sulfur help break down blackheads and whiteheads. Salicylic acid also helps cut down the shedding of cells lining the follicles of the oil glands. Topical OTC medications are available in many forms, such as gel, lotion, cream, soap, or pad.

In some patients, OTC acne medications may cause side effects such as skin irritation, burning, or redness. Some people find that the side effects lessen or go away with continued use of the medication. Severe or prolonged side effects should be reported to the doctor.

OTC topical medications are usually moderately effective in treating acne when used regularly. Patients must keep in mind that it can take between 4 and 8 weeks before they notice an improvement in their skin.

Prescription Topical Medications

Several types of prescription topical medications are used to treat acne, including benzoyl peroxide, antibiotics, tretinoin, adapalene, and azelaic acid. Prescription and OTC benzoyl peroxide work in the same way. Many doctors prescribe benzoyl peroxide instead of recommending OTC versions to make sure patients get the most desirable formulation (cream, gel, or lotion).

Antibiotics and azelaic acid help stop or slow the growth of P. acnes and reduce inflammation. Tretinoin, a type of drug called a retinoid that contains vitamin A, is the most effective topical medication for stopping the development of new comedones. It also fights acne by increasing cell turnover, which helps unplug existing comedones, and thereby allows other topical medications, such as antibiotics, to penetrate the follicles better. The doctor may also prescribe a newer drug called adapalene gel, a retinoidlike compound that helps decrease microcomedone formation.

Prescription topical medications come in a variety of products. The doctor will consider the patient’s skin type when prescribing a product. Creams and lotions are moisturizing and tend to be good for people with dry skin. Gels and solutions are generally alcohol based and tend to dry the skin, so patients with excessively oily skin or those who live in hot, humid climates may prefer a gel. The doctor will tell the patient how to apply the medication and how often to use it.

Some people develop side effects from using prescription topical medications. Common side effects include stinging, burning, redness, peeling, scaling, or discoloration of the skin. With retinoids, these side effects usually decrease or go away after the medication is used for a period of time. Patients should report prolonged or severe side effects to their doctor. Between 4 and 8 weeks will most likely pass before patients see improvement in their skin.

Prescription Oral Medications

For patients with moderate to severe acne, the doctor often prescribes oral antibiotics (taken by mouth) in addition to topical medication. Oral antibiotics are thought to help control acne by curbing the growth of P. acnes and decreasing inflammation. Common antibiotics used to treat acne are tetracycline, minocycline, doxycycline, and erythromycin. Some people have side effects when taking these antibiotics, such as photosensitivity (higher risk of sunburn), upset stomach, dizziness or lightheadedness, and skin discoloration. Tetracycline is not given to pregnant women or children under 12 years of age because it can discolor developing teeth. Tetracycline and minocycline also decrease the effectiveness of birth control pills, so a backup or alternative form of birth control must be used. Patients usually must take oral antibiotics for as long as 4 to 6 months to effectively treat acne.

Treatment for Severe Nodular or Cystic Acne

People with severe nodular or cystic acne should be treated by a dermatologist. For patients with severe inflammatory acne that does not improve with other medications, such as those described above, isotretinoin (Accutane), a retinoid, may be needed. Isotretinoin is an oral drug and is usually taken once or twice a day for 16 to 20 weeks. It is believed to markedly reduce the size of the oil glands so that much less oil is produced. As a result, the growth of P. acnes is decreased. Isotretinoin also reduces cell shedding and the stickiness of cells in the follicles, which helps prevent the development of comedones.

Advantages of Isotretinoin

Isotretinoin is a very effective medication that can help prevent extensive scarring in patients. After 16 to 20 weeks of treatment with isotretinoin, acne completely or almost completely goes away in most patients (up to 90 percent). For some people, however, the acne will come back, and they will need additional treatment with isotretinoin.

Disadvantages of Isotretinoin

Patients should carefully consider the several disadvantages of isotretinoin. The drug is not only expensive but is also linked to some adverse effects that can be severe. Possible side effects include inflammation of the lip and mucous membrane of the eye; dry mouth, nose, or skin; itching; nosebleeds; muscle aches; photosensitivity; and, rarely, decreased night vision. Other more serious side effects include increased blood cholesterol, lipid, and triglyceride levels and abnormal liver enzymes. To make sure isotretinoin is stopped if these side effects occur, the doctor usually monitors a patient’s complete blood count, blood chemistries, cholesterol, triglycerides, and liver enzymes before therapy is started and periodically during treatment. All of these side effects usually go away after the medication is stopped. Patients who experience side effects while using isotretinoin should tell their doctor. The doctor may be able to reduce the dose of the drug so that the side effects are decreased or stopped.

The most serious potential adverse effect of isotretinoin is that it is teratogenic: it can cause birth defects in the developing fetus of pregnant women who take the drug. Therefore, it is crucial that women of childbearing age are not pregnant and do not get pregnant while taking isotretinoin. Women must use an appropriate birth control method for 1 month before therapy begins, during the entire course of therapy, and for 1 full month after therapy stops. Women should talk to their doctor about when it is safe to get pregnant after therapy with isotretinoin has stopped.

Treatments for Hormonally Influenced Acne

For some female patients, treatment-resistant acne is caused by excessive production of hormones called androgens. Clues that help the doctor diagnose hormonally influenced acne are adult-onset acne, hirsutism (excessive growth of hair or hair in unusual places), premenstrual acne flares, irregular menstrual cycles, and elevated blood levels of certain androgens.

The doctor may prescribe one of several drugs to treat women with this type of acne. Low-dose estrogen birth control pills help suppress the androgen produced by the ovaries. Low-dose corticosteroid drugs, such as prednisone or dexamethasone, may have an anti-inflammatory effect and suppress the androgen produced by the adrenal glands. Finally, the doctor may prescribe an antiandrogen drug, such as spironolactone, which helps prevent androgens from causing excessive oil production. Spironolactone also stops androgen production in the ovaries and adrenal glands. Side effects of antiandrogen drugs may include menstrual irregularities, breast tenderness, headache, and fatigue.

Other Treatments for Acne

Doctors may use other types of procedures in addition to drug therapy to treat patients with acne. The doctor may remove the patient’s comedones during office visits. Sometimes the doctor will inject a corticosteroid drug directly into lesions to help reduce the size and symptoms of tender and inflamed cysts and nodules. Other patients may benefit from light skin-peeling agents that are prescribed by a doctor or applied in the doctor’s office. For some patients, the doctor may suggest a minor surgical or medical procedure to help reduce scarring caused by acne.

How Should People With Acne Care for Their Skin?

Clean Skin Gently

People with acne may try to stop outbreaks and oil production by scrubbing their skin and using strong detergent soaps. However, scrubbing will not improve acne; in fact, it can make the problem worse. Most doctors recommend that people with acne gently wash their skin with a mild cleanser, once in the morning and once in the evening. Patients should ask their doctor or another health professional for advice on the best type of cleanser to use. The skin should also be washed after heavy exercise. Patients should wash their face from under the jaw to the hairline; rough scrubs or pads should not be used. It is important that patients thoroughly rinse their skin after washing it. Astringents are not recommended unless the skin is very oily, and then they should be used only on oily spots. Doctors also recommend that patients regularly shampoo their hair. Those with oily hair may want to shampoo it every day.

Avoid Frequent Handling of the Skin

People who squeeze, pinch, or pick their blemishes risk developing scars. Acne lesions can form in areas where pressure is frequently applied to the skin. Frequent rubbing and touching of skin lesions should be avoided.

Shave Carefully

Men who shave and who have acne can try electric and safety razors to see which is more comfortable. Men who use a safety razor should use a sharp blade and soften their beard thoroughly with soap and water before applying shaving cream. Nicking blemishes can be avoided by shaving lightly and only when necessary.

Avoid Suntanning

A suntan or sunburn that reddens the skin can make blemishes less visible and make the skin feel drier for a little while. But the benefits are only temporary. The sun can seriously damage skin, promote aging of skin, and cause skin cancer. Furthermore, many of the medications used to treat acne make a person more prone to sunburn.

Choose Cosmetics Carefully

People being treated for acne often need to change some of the cosmetics they use. All cosmetics, such as foundation, blush, eye shadow, and moisturizers, should be oil free. Patients may find it difficult to apply foundation evenly during the first few weeks of treatment because skin may be red or scaly, particularly with the use of topical tretinoin or benzoyl peroxide. Lip products that contain moisturizers may cause small, open and closed comedones to form. Hairstyling products that come in contact with the skin along the hairline can cause burning or stinging in people with acne. Products that are labeled as noncomedogenic (do not promote the formation of blemishes) should be used; in some people, however, even these products may cause acne.

What Research Is Being Done on Acne?

Medical researchers are working to develop new topical antibiotics for treating acne to replace some of those in current use. As with many other types of bacterial infections, doctors are finding that, over time, the bacteria that cause acne are becoming resistant to treatment with certain antibiotics. A different type of antibiotic or a stronger one is needed to kill disease-causing bacteria once they become resistant to existing antibiotics.

Research is being conducted on lipophilic compounds, a class of drugs that are potent in decreasing inflammation and killing P. acnes. Additional research is also being conducted on the potential side effects of isotretinoin and the long-term use of medications used for treating acne.

Other researchers are attempting to determine the factors in girls during early puberty that might predict the development of severe acne later. Finally, some researchers are studying how acne affects certain aspects of patients’ lives, including psychological health and quality of life.

Where Can People Find More Information on Acne?

• American Academy of Dermatology
  P.O. Box 4014
  Schaumburg, IL 60168–4014
  (847) 330–0230
  Fax: (847) 330–0050
  World Wide Web address: http://www.aad.org/

This national organization for dermatologists publishes a brochure on acne. The brochure can be obtained by calling or writing to the academy; it is also available on the organization’s Web site. The academy can also provide referrals to dermatologists.

• National Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse
  (NAMSIC)
  National Institutes of Health
  1 AMS Circle
  Bethesda, MD 20892–3675
  301/495–4484
  Fax: 301/718–6366
  TTY: 301/565–2966
  NIAMS Fast Facts—For health information that is available 24 hours a day by fax, call 301/881–2731 from a fax machine telephone.
  World Wide Web address: http://www.nih.gov/niams/

This clearinghouse, a public service sponsored by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), provides information about various forms of arthritis and musculoskeletal and skin diseases. The clearinghouse distributes patient and professional education materials and also refers people to other sources of information.

Acknowledgments

The NIAMS gratefully acknowledges the assistance of Alan Moshell, M.D., NIAMS, NIH; Gary Peck, M.D., Washington Hospital Center, Washington, DC; and Larry Miller, M.D., Chevy Chase, MD.

Back to the Top