Causes

Four main factors cause acne:

  • Oil production
  • Dead skin cells
  • Clogged pores
  • Bacteria

Acne typically appears on your face, neck, chest, back and shoulders. These areas of skin have the most oil (sebaceous) glands. Acne occurs when hair follicles become plugged with oil and dead skin cells.

Hair follicles are connected to oil glands. These glands secrete an oily substance (sebum) to lubricate your hair and skin. Sebum normally travels along the hair shafts and 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. They form a soft plug, creating an environment where bacteria can thrive. If the clogged pore becomes infected with bacteria, inflammation results.

The plugged pore 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. A blackhead may look like dirt stuck in pores. But actually the pore is congested with bacteria and oil, which turns brown when it’s exposed to the air.

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 cyst-like lumps beneath the surface of your skin. Other pores in your skin, which are the openings of the sweat glands, aren’t usually involved in acne.

Factors that may worsen acne

These factors can trigger or aggravate an existing case of acne:

  • 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 also can affect sebum production. And low amounts of androgens circulate in the blood of women and can worsen acne.
  • Certain medications.Drugs containing corticosteroids, androgens or lithium can worsen acne.
  • Studies indicate that certain dietary factors, including dairy products and carbohydrate-rich foods — such as bread, bagels and chips — may trigger acne. Chocolate has long been suspected of making acne worse. A recent study of 14 men with acne showed that eating chocolate was related to an increase in acne. Further study is needed to examine why this happens or whether acne patients need to follow specific dietary restrictions.
  • Stress can make acne worse.

Acne myths

These factors have little effect on acne:

  • Greasy foods.Eating greasy food has little to no effect on acne. Though working in a greasy area, such as a kitchen with fry vats, does because the oil can stick to the skin and block the hair follicles. This further irritates the skin or promotes 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. Though it does help to gently remove oil, dead skin and other substances.
  • Cosmetics don’t necessarily worsen acne, especially if you use oil-free makeup that doesn’t clog pores (noncomedogenics) and remove makeup regularly. Nonoily cosmetics don’t interfere with the effectiveness of acne drugs.

Risk factors

Risk factors for acne include:

  • Hormonal changes.Such changes are common in teenagers, women and girls, and people using certain medications, including those containing corticosteroids, androgens or lithium.
  • Family history.Genetics plays a role in acne. If both parents had acne, you’re likely to develop it, too.
  • Greasy or oily substances.You may develop acne where your skin comes into contact with oily lotions and creams or with grease in a work area, such as a kitchen with fry vats.
  • Friction or pressure on your skin.This can be caused by items such as telephones, cellphones, helmets, tight collars and backpacks.
  • This doesn’t cause acne, but if you have acne already, stress may make it worse.

Treatments and drugs

If over-the-counter (nonprescription) products haven’t cleared up your acne, your doctor can prescribe stronger medications or other therapies. A dermatologist can help you:

  • Control your acne
  • Avoid scarring or other damage to your skin
  • Make scars less noticeable

Acne medications work by reducing oil production, speeding up skin cell turnover, fighting bacterial infection or reducing inflammation — which helps prevent scarring. With most prescription acne drugs, you may not see results for four to eight weeks, and your skin may get worse before it gets better. It can take many months or years for your acne to clear up completely.

The drug your doctor recommends depends on the type and severity of your acne. It might be something you apply to your skin (topical medication) or take by mouth (oral medication). Often, drugs are used in combination. Pregnant women will not be able to use oral prescription medications for acne.

Talk with your doctor about the risks and benefits of medications and other treatments you are considering.

Topical medications

These products work best when applied to clean, dry skin about 15 minutes after washing. You may not see the benefit of this treatment for a few weeks. And you may notice skin irritation at first, such as redness, dryness and 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.

The most common topical prescription medications for acne are:

  • These come as creams, gels and lotions. Retinoid drugs are derived from vitamin A and include tretinoin (Avita, Retin-A, others), adapalene (Differin) and tazarotene (Tazorac, Avage). You apply this medication in the evening, beginning with three times a week, then daily as your skin becomes used to it. It works by preventing plugging of the hair follicles.
  • These work by killing excess skin bacteria and reducing redness. For the first few months of treatment, you may use both a retinoid and an antibiotic, with the antibiotic applied in the morning and the retinoid in the evening. The antibiotics are often combined with benzoyl peroxide to reduce the likelihood of developing antibiotic resistance. Examples include clindamycin with benzoyl peroxide (Benzaclin, Duac, Acanya) and erythromycin with benzoyl peroxide (Benzamycin).
  • Dapsone (Aczone).This gel is most effective when combined with a topical retinoid. Skin side effects include redness and dryness.

Oral medications

  • For moderate to severe acne, you may need oral antibiotics to reduce bacteria and fight inflammation. Choices for treating acne include tetracyclines, such as minocycline and doxycycline.

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. Tapering helps prevent antibiotic resistance by minimizing undue exposure to these medications over a long time.

You will likely 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 and dizziness. These drugs also increase your skin’s sun sensitivity. They can cause discoloration of developing permanent teeth and reduced bone growth in children born to women who took tetracyclines while pregnant.

  • Combined oral contraceptives.Combined oral contraceptives are useful in treating acne in women and adolescent girls. The Food and Drug Administration approved three products that combine estrogen and progestin (Ortho Tri-Cyclen, Estrostep and Yaz).

The most common side effects of these drugs are headache, breast tenderness, nausea, weight gain and breakthrough bleeding. A serious potential complication is a slightly increased risk of blood clots.

  • Anti-androgen agent.The drug spironolactone (Aldactone) may be considered for women and adolescent girls if oral antibiotics aren’t helping. It works by blocking the effect of androgen hormones on the sebaceous glands. Possible side effects include breast tenderness, painful periods and the retention of potassium.
  • This medicine is reserved for people with the most severe acne. Isotretinoin (Amnesteem, Claravis, Sotret) is a powerful drug for people whose acne doesn’t respond to other treatments.

Oral isotretinoin is very effective. But because of its potential side effects, doctors need to closely monitor anyone they treat with this drug. The most serious potential side effects include ulcerative colitis, an increased risk of depression and suicide, and severe birth defects.

In fact, isotretinoin carries such serious risk of 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.

Therapies

These therapies may be suggested in select cases, either alone or in combination with medications.

  • Light therapy.A variety of light-based therapies have been tried with success. But further study is needed to determine the ideal method, light source and dose. Light therapy targets the bacteria that cause acne inflammation. Some types of light therapy are done in a doctor’s office. Blue-light therapy can be done at home with a hand-held device.

Possible side effects of light therapy include pain, temporary redness and sensitivity to sunlight.

  • Chemical peel.This procedure uses repeated applications of a chemical solution, such as salicylic acid. It is most effective when combined with other acne treatments, except oral retinoids. Chemical peels aren’t recommended for people taking oral retinoids because together these treatments can significantly irritate the skin.

Chemicals peels may cause temporary, severe redness, scaling and blistering, and long-term discoloration of the skin.

  • Extraction of whiteheads and blackheads.Your dermatologist uses special tools to gently remove whiteheads and blackheads (comedos) that haven’t cleared up with topical medications. This technique may cause scarring.
  • Steroid injection.Nodular and cystic lesions can be treated by injecting a steroid drug directly into them. This improves their appearance without the need for extraction. The side effects of this technique include thinning of the skin, lighter skin and the appearance of small blood vessels on the treated area.

Treating acne scars

Procedures used to diminish scars left by acne include the following:

  • Soft tissue fillers.Injecting soft tissue fillers, such as collagen or fat, under the skin and into indented scars can fill out or stretch the skin. This makes the scars less noticeable. Results are temporary, so you would need to repeat the injections periodically. Side effects include temporary swelling, redness and bruising.
  • Chemical peels.High-potency acid is applied to your skin to remove the top layer and minimize deeper scars.
  • This procedure is usually reserved for more severe scarring. It involves sanding (planing) the surface layer of skin with a rotating brush. This helps blend acne scars into the surrounding skin.
  • Laser resurfacing.This is a skin resurfacing procedure that uses a laser to improve the appearance of your skin.
  • Light therapy.Certain lasers, pulsed light sources and radiofrequency devices that don’t injure the epidermis can be used to treat scars. These treatments heat the dermis and cause new skin to form. After several treatments, acne scars may appear less noticeable. This treatment has shorter recovery times than some other methods. But you may need to repeat the procedure more often and results are subtle.
  • Skin surgery.Using a minor procedure called punch excision, your doctor cuts out individual acne scars and repairs the hole at the scar site with stitches or a skin graft.