DefinitionSymptomsCausesRisk factorsComplicationsTreatments and drugs Acne is a skin condition that occurs when your hair follicles become plugged with oil and dead skin cells. Acne most commonly appears on your face, neck, chest, back and shoulders. Acne can be distressing and annoyingly persistent. Acne lesions heal slowly, and when one begins to resolve, others seem to crop up. Depending on its severity, acne can cause emotional distress and lead to scarring of the skin. The good news is that effective treatments are available — and the earlier treatment is started, the lower your risk of lasting physical and emotional damage. Acne typically appears on your face, neck, chest, back and shoulders, which are the areas of your skin with the largest number of functional oil glands. Acne can take the following forms: Noninflammatory lesions Comedones (whiteheads and blackheads) are created when the openings of hair follicles become clogged and blocked with oil secretions, dead skin cells and sometimes bacteria. When comedones (koe-muh-DOE-neez) are open at the skin surface, they’re called blackheads because of the dark appearance of the plugs in the hair follicles. When comedones are closed, they’re called whiteheads — slightly raised, skin-colored bumps. Inflammatory lesions Papules are small raised bumps that signal inflammation or infection in the hair follicles. Papules may be red and tender. Pustules (pimples) are red, tender bumps with white pus at their tips. Nodules are large, solid, painful lumps beneath the surface of the skin. They’re formed by the buildup of secretions deep within hair follicles. Cysts are painful, pus-filled lumps beneath the surface of the skin. These boil-like infections can cause scars. When to see a doctor Acne usually isn’t a serious medical condition. But you may want to seek medical treatment from a dermatologist for persistent pimples or inflamed cysts to avoid scarring or other damage to your skin. If acne and the scars it may have left are affecting your social relationships or self-esteem, you may also want to ask a dermatologist if your acne can be controlled or if your scars can be diminished. Three factors contribute to the formation of acne: Overproduction of oil (sebum) Irregular shedding of dead skin cells resulting in irritation of the hair follicles of your skin Buildup of bacteria Acne occurs when the hair follicles become plugged with oil and dead skin cells. Hair follicles are connected to sebaceous glands. These glands secrete an oily substance known as sebum to lubricate your hair and skin. Sebum normally travels up along the hair shafts and then out through the openings of the hair follicles onto the surface of your skin. When your body produces an excess amount of sebum and dead skin cells, the two can build up in the hair follicles and form together as a soft plug, creating an environment where bacteria can thrive. This plug may cause the follicle wall to bulge and produce a whitehead. Or, the plug may be open to the surface and may darken, causing a blackhead. Pimples are raised red spots with a white center that develop when blocked hair follicles become inflamed or infected. Blockages and inflammation that develop deep inside hair follicles produce lumps beneath the surface of your skin called cysts. Other pores in your skin, which are the openings of the sweat glands onto your skin, aren’t normally involved in acne. Factors that may worsen acne These factors can trigger or aggravate an existing case of acne: Hormones. Androgens are hormones that increase in boys and girls during puberty and cause the sebaceous glands to enlarge and make more sebum. Hormonal changes related to pregnancy and the use of oral contraceptives can also affect sebum production. Certain medications. Drugs containing corticosteroids, androgens or lithium are known to cause acne. Diet. Studies indicate that certain dietary factors, including dairy products and carbohydrate-rich foods — such as bread, bagels and chips, which increase blood sugar — may trigger acne. Acne myths Contrary to what some people think, these factors have little effect on acne: Greasy foods and chocolate have proved to have little to no effect on the development or course of acne. Dirty skin. Acne isn’t caused by dirt. In fact, scrubbing the skin too hard or cleansing with harsh soaps or chemicals irritates the skin and can make acne worse. Simple cleansing of the skin to remove excess oil and dead skin cells is all that’s required. Hormonal changes in your body can provoke or aggravate acne. Such changes are common in: Teenagers Women and girls, two to seven days before their periods Pregnant women People using certain medications, including those containing corticosteroids, androgens or lithium Other risk factors include: Direct skin contact with greasy or oily substances, or to certain cosmetics applied directly to the skin A family history of acne — if your parents had acne, you’re likely to develop it, too Friction or pressure on your skin caused by various items, such as telephones or cellphones, helmets, tight collars and backpacks Stress doesn’t cause acne, but if you have acne already, stress may make it worse Acne treatments work by reducing oil production, speeding up skin cell turnover, fighting bacterial infection, reducing the inflammation or doing all four. With most prescription acne treatments, you may not see results for four to eight weeks, and your skin may get worse before it gets better. Your doctor or dermatologist may recommend a prescription medication you apply to your skin (topical medication) or take by mouth (oral medication). Oral prescription medications for acne should not be used during pregnancy, especially during the first trimester. Types of acne treatments include: Over-the-counter topical treatments. Acne lotions may dry up the oil, kill bacteria and promote sloughing of dead skin cells. Over-the-counter (OTC) lotions are generally mild and contain benzoyl peroxide, sulfur, resorcinol, salicylic acid or sulfur as their active ingredient. These products can be helpful for very mild acne. OTC acne medications may cause initial side effects — such as skin irritation, dryness and flaking — that often improve after the first month of therapy. Topical treatments available by prescription. If your acne doesn’t respond to OTC treatments, consider seeing a doctor or dermatologist to get a stronger prescription lotion. Tretinoin (Avita, Retin-A, others), adapalene (Differin) and tazarotene (Tazorac, Avage) are examples of topical prescription products derived from vitamin A. They work by promoting cell turnover and preventing plugging of the hair follicles. A number of topical antibiotics also are available. They work by killing excess skin bacteria. Often, a combination of such products is required to achieve optimal results. A number of benzoyl peroxide and antibiotic combination medications are available, including different dose combinations of benzoyl peroxide and clindamycin (Benzaclin, Duac, Acanya) and benzoyl peroxide and erythromycin (Benzamycin). Dapsone gel (Aczone) is a newer acne treatment that’s particularly effective in treating inflammatory acne. Prescription topical treatments for acne may cause skin side effects, such as stinging, burning, redness or peeling. Your doctor may recommend steps to minimize these side effects, including using a gradually increased dose, washing off the medication after a short application or switching to another medication. Antibiotics. For moderate to severe acne, you may need a short course of prescription oral antibiotics to reduce bacteria and fight inflammation. Since oral antibiotics were first used to treat acne, antibiotic resistance has increased significantly in people with acne. For this reason, your doctor likely will recommend tapering off these medications as soon as your symptoms begin to improve, or as soon as it becomes clear the drugs aren’t helping — usually, within three to four months. In most cases, you’ll use topical medications and oral antibiotics together. Studies have found that using topical benzoyl peroxide along with oral antibiotics may reduce the risk of developing antibiotic resistance. Antibiotics may cause side effects, such as an upset stomach, dizziness or skin discoloration. These drugs also increase your skin’s sun sensitivity and may reduce the effectiveness of oral contraceptives. Isotretinoin. For deep cysts, antibiotics may not be enough. Isotretinoin (Amnesteem, Claravis, Sotret) is a powerful medication available for scarring cystic acne or acne that doesn’t respond to other treatments. This medicine is reserved for the most severe forms of acne. It’s very effective, but people who take it need close monitoring by a dermatologist because of the possibility of severe side effects. Isotretinoin is associated with severe birth defects, so it can’t be safely taken by pregnant women or women who may become pregnant during the course of treatment or within several weeks of concluding treatment. In fact, the drug carries such serious potential side effects that women of reproductive age must participate in a Food and Drug Administration-approved monitoring program to receive a prescription for the drug. Isotretinoin commonly causes side effects — such as dry eyes, mouth, lips, nose and skin, as well as itching, nosebleeds, muscle aches, sun sensitivity and poor night vision. The drug may also increase the levels of triglycerides and cholesterol in the blood and may increase liver enzyme levels. In addition, isotretinoin may be associated with an increased risk of depression and suicide. Although this causal relationship has not been proved, doctors remain on alert for these signs in people who are taking isotretinoin. If you feel unusually sad or unable to cope while taking this drug, tell your doctor immediately. Oral contraceptives. Oral contraceptives, including a combination of norgestimate and ethinyl estradiol (Ortho Tri-Cyclen, Previfem, others), can improve acne in women. However, oral contraceptives may cause other side effects — such as headaches, breast tenderness, nausea and depression — that you’ll want to discuss with your doctor. The most serious potential complication is a slightly increased risk of heart disease, high blood pressure and blood clots. Laser and light therapy. Laser- and light-based therapies reach the deeper layers of skin without harming the skin’s surface. Laser treatment is thought to damage the oil (sebaceous) glands, causing them to produce less oil. Light therapy targets the bacteria that cause acne inflammation. These therapies can also improve skin texture and lessen the appearance of scars. More research is needed to understand the most effective use of light and laser therapies in acne treatment, and experts currently recommend these approaches as stand-alone therapy only in people who can’t tolerate approved acne medications. These therapies may be uncomfortable and may cause temporary skin problems that mimic a severe sunburn. Cosmetic procedures. Chemical peels and microdermabrasion may be helpful in controlling acne. These cosmetic procedures — which have traditionally been used to lessen the appearance of fine lines, sun damage and minor facial scars — are most effective when used in combination with other acne treatments. They may cause temporary, severe redness, scaling and blistering, and long-term discoloration of the skin. Acne scar treatment Doctors may be able to use certain procedures to diminish scars left by acne. These include fillers, dermabrasion, intense light therapy and laser resurfacing. Soft tissue fillers. Collagen or fat can be injected under the skin and into scars to fill out or stretch the skin, making the scars less noticeable. Results from this acne scar treatment are temporary, so you need to repeat the injections periodically. Chemical peels. High-potency acid is applied to your skin to remove the top layer and minimize deeper scars. Some stronger peels reach even deeper into the skin. Dermabrasion. Usually reserved for more severe scarring, dermabrasion involves removing the top layer of skin with a rapidly rotating wire brush. Surface scars may be completely removed, and deeper acne scars may appear less noticeable. Dermabrasion may cause pigmentation changes for people with darker skin. Microdermabrasion. This newer acne scar treatment involves a hand-held device that blows crystals onto skin. These crystals gently abrade or “polish” the skin’s surface. Then, a vacuum tube removes the crystals and skin cells. Because just the surface cells are removed, the skin isn’t damaged. However, results are subtle and scars may still be noticeable, even after several sessions. Laser, light source and radiofrequency treatments. In laser resurfacing, a laser beam destroys the outer layer of skin (epidermis) and heats the underlying skin (dermis). As the wound heals, new skin forms. Less intense lasers (nonablative lasers), pulsed light sources and radiofrequency devices don’t injure the epidermis. These treatments heat the dermis and cause new skin formation. After several treatments, acne scars may appear less noticeable. This means shorter recovery times, but treatment typically needs to be repeated more often and results are subtle. Skin surgery. A minor procedure (punch excision) cuts out individual acne scars. Stitches or a skin graft repairs the hole left at the scar site.