Treatment of mild acne should be continued for 6 wk or until lesions respond. Maintenance treatment may be necessary to maintain control.

Single-agent therapy is generally sufficient for comedonal acne. A mainstay of treatment for comedones is daily topical tretinoin as tolerated. Daily adapalene gel, tazarotene cream or gel, azelaic acid cream, and glycolic or salicylic acid are alternatives for patients who cannot tolerate topical tretinoin. Adverse effects include erythema, burning, stinging, and peeling. Adapalene and tazarotene are retinoids; like tretinoin, they tend to be somewhat irritating and photosensitizing. Azelaic acid has comedolytic and antibacterial properties by an unrelated mechanism and may be synergistic with retinoids.

Dual therapy (eg, a combination of tretinoin with benzoyl peroxide, a topical antibiotic, or both) should be used to treat mild papulopustular (inflammatory) acne. The topical antibiotic is usually erythromycin or clindamycin. Combining benzoyl peroxide with these antibiotics may help limit development of resistance. Glycolic acid may be used instead of or in addition to tretinoin. Treatments have no significant adverse effects other than drying and irritation (and rare allergic reactions to benzoyl peroxide).

Physical extraction of comedones using a comedone extractor is an option for patients unresponsive to topical treatment. Comedone extraction may be done by a physician, nurse, or physician assistant. One end of the comedone extractor is like a blade or bayonet that punctures the closed comedone. The other end exerts pressure to extract the comedone.

Oral antibiotics (eg, tetracycline, minocycline, doxycycline, erythromycin) can be used when wide distribution of lesions makes topical therapy impractical.

Oral systemic therapy with antibiotics is the best way to treat moderate acne. Antibiotics effective for acne include tetracycline, minocycline, erythromycin, and doxycycline. Full benefit takes ≥ 12 wk.

Topical therapy as for mild acne is usually used concomitantly with oral antibiotics.

Doxycycline and minocycline are first-line drugs; both can be taken with food. Tetracycline is also a good first choice, but it cannot be taken with food and may have lower efficacy than doxycycline and minocycline. Doxycycline and minocycline dosage is 50 to 100 mg po bid. Doxycycline may cause photosensitivity, and minocycline may have more adverse effects with chronic use, including drug-induced lupus and hyperpigmentation. Tetracycline dosage is 250 or 500 mg po bid between meals. To reduce the development of antibiotic resistance after control is achieved (usually 2 to 3 mo), the dose is tapered as much as possible to maintain control. Antibiotics may be discontinued if topical therapy maintains control.

Erythromycin is another option, but it can cause GI adverse effects and antibiotic resistance develops more often.

Long-term use of antibiotics may cause a gram-negative pustular folliculitis around the nose and in the center of the face. This uncommon superinfection may be difficult to clear and is best treated with oral isotretinoin after discontinuing the oral antibiotic. Ampicillin is an alternative treatment for gram-negative folliculitis. In women, prolonged antibiotic use can cause candidal vaginitis; if local and systemic therapy does not eradicate this problem, antibiotic therapy for acne must be stopped.

If the patient is female and unresponsive to oral antibiotics, a trial of oral antiandrogens (oral contraceptives and/or spironolactone) may be considered.

Oral isotretinoin is the best treatment for patients with moderate acne in whom antibiotics are unsuccessful and for those with severe inflammatory acne. Dosage of isotretinoin is usually 1 mg/kg once/day for 16 to 20 wk, but the dosage may be increased to 2 mg/kg once/day. If adverse effects make this dosage intolerable, it may be reduced to 0.5 mg/kg once/day. After therapy, acne may continue to improve. Most patients do not require a 2nd course of treatment; when needed, it should be resumed only after the drug has been stopped for 4 mo. Retreatment is required more often if the initial dosage is low (0.5 mg/kg). With this dosage (which is very popular in Europe), fewer adverse effects occur, but prolonged therapy is usually required. Cumulative dosing has gained support; a total dosage of 120 to 150 mg/kg resulted in lower recurrence rates.

Isotretinoin is nearly always effective, but use is limited by adverse effects, including dryness of conjunctivae and mucosae of the genitals, chapped lips, arthralgias, depression, elevated lipid levels, and the risk of birth defects if treatment occurs during pregnancy. Hydration with water followed by petrolatum application usually alleviates mucosal and cutaneous dryness. Arthralgias (mostly of large joints or the lower back) occur in about 15% of patients. Increased risk of depression and suicide is much publicized but probably rare. It is not clear whether risk of new or worsened inflammatory bowel disease (Crohn disease and ulcerative colitis) is increased.

CBC, liver function, and fasting glucose, triglyceride, and cholesterol levels should be determined before treatment. Each should be reassessed at 4 wk and, unless abnormalities are noted, need not be repeated until the end of treatment. Triglycerides rarely increase to a level at which the drug should be stopped. Liver function is seldom affected. Because isotretinoin is teratogenic, women of childbearing age are told that they are required to use 2 methods of contraception for 1 mo before treatment, during treatment, and for at least 1 mo after stopping treatment. Pregnancy tests should be done before beginning therapy and monthly until 1 mo after therapy stops.

Intralesional injection of 0.1 mL triamcinolone acetonide suspension 2.5 mg/mL (the 10 mg/mL suspension must be diluted) is indicated for patients with firm (cystic) acne who seek quick clinical improvement with reduced scarring. Local atrophy may occur but is usually transient. For isolated, very boggy lesions, incision and drainage are often beneficial but may result in residual scarring.

Pyoderma faciale is treated with oral corticosteroids and isotretinoin.

Acne fulminans is treated with oral corticosteroids and systemic antibiotics.

Acne conglobata is treated with oral isotretinoin if systemic antibiotics fail.

For acne caused by endocrine abnormalities (eg, polycystic ovary syndrome, virilizing adrenal tumors in females), antiandrogens are indicated. Spironolactone, which has some antiandrogen effects, is sometimes prescribed to treat acne at a dose of 50 to 100 mg po once/day. Cyproterone acetate is used in Europe. When other measures fail, an estrogen/progesterone–containing contraceptive may be tried; therapy ≥ 6 mo is needed to evaluate effect.

Small scars can be treated with chemical peels, laser resurfacing, or dermabrasion. Deeper, discrete scars can be excised. Wide, shallow depressions can be treated with subcision or collagen injection. Collagen implants are temporary and must be repeated every few years.