May 2001

Tip of the Month

Some skin and hair-care cosmetics can cause outbreaks of comedones, as described in the Main Text section Why and how acne happens. This is called acnegenicity—the ability to induce acne.

The term acnegenicity refers to both:
comedogenicity—the ability to induce comedones (blackheads and whiteheads), and papule and pustule formation.

Papules and pustules induced by a cosmetic usually appear within a few days after the cosmetic is used. Comedones begin to appear later.

Most cosmetics made and marketed by large cosmetics firms in the United States are tested for acnegenicity and labeled as noncomedogenic (not causing comedones to form). Even when a cosmetic is so labeled, however, it should be used with care by anyone who has, or has had, acne:
Cosmetics should be used sparingly by a person with acne, or a history of acne.
Any cosmetic that is used should be labeled as noncomedogenic.
When cosmetics are removed, cleansing should be with gentle cleansers or plain soap and water, and should be done without harsh scrubbing.
Regardless of whether a cosmetic is labeled as noncomedogenic, if acne lesions appear after its use any future use should be avoided.

Many persons today are interested in cosmetics that claim to contain “natural,” “herbal” or “organic” ingredients. A person with acne should be cautious in their use:
Regardless of other claims, a cosmetic should be avoided if it is not labeled as noncomedogenic; and
The possibility of other skin sensitivities should be kept in mind, and the cosmetic discontinued if the skin becomes excessively dry, scaly, inflamed or itchy.

Fact of the Month

This month, Fact of the Month offers the second in a three-part update on acne treatments. This month’s update covers prescribed topical medications. Over-the-counter topical medications were discussed last month. Next month, information on systemic medications will be updated.

Prescribed Topical Medications

The most effective acne medications are available only by physician prescription. As with any potent pharmaceutical agent, they should be used only after examination by a physician and under the supervision of a physician. Prescribed topical medications include the topical antibiotics and topical retinoids.

Topical Antibiotics

The antibiotics used topically in treatment of acne are believed to be effective for reasons in addition to anti-bacterial activity. All antibiotics are powerful drugs that must be used as directed by a physician. Topical antibiotics alone are not generally recommended. In fact, long-term use may increase risk for antibiotic resistance in skin bacteria. They should be used in combination with other topical agents. 

Azelaic acid—a naturally occurring acid that has been adapted to use for treating acne. Its anti-acne activities are antimicrobial (reducing populations of Propionibacterium acnes ), and decrease of hyper-keratinization (may inhibit comedo formation). P. acnes is the predominant microbiologic organism in sebaceous follicles. It is generally accepted that P. acnes plays a role in acne by releasing metabolic products that contribute to the inflammation of acne (Click on Why and How Acne Happens for more information on the causes of acne). Azelaic acid is applied as a cream. A course of treatment may require several months.

Erythromycin—a member of the macrolide family of antibiotics, erythromycin is active against a broad spectrum of bacteria. Systemically it is used to treat diseases such as pneumonia. Its principal topical use is in treatment of acne vulgaris, for its anti-acne effects are both antimicrobial and anti-inflammatory. A combination erythromycin/benzoyl peroxide agent combines the effects of two antimicrobial agents plus reduction of skin oiliness. A combination erythromycin/zinc acetate is available in some countries but not currently in the United States.

Clindamycin—a semisynthetic antibiotic with antimicrobial activity similar to that of erythromycin. Clindamycin has a long history of use in treatment of acne.

Tetracycline—This group of broad-spectrum antibiotics were among the first antibiotics adapted to the topical treatment of acne, but today are used much less frequently in the United States as topical medication. Undesirable side effects of odor and yellow staining of skin limited the acceptance of tetracycline topical agents.

Sulfonamide—The sulfonamides are among the oldest antibacterial agents, in use since the 1930s. Sodium sulfonamide lotion is available for treatment of acne and reducing inflammatory lesions.

Many other antibiotics are used topically to treat skin infections. The antibiotics discussed above are those in current topical use in the United States to treat acne vulgaris. A dermatologist can determine for each individual patient (1) whether topical antibiotics are appropriate, and (2) which topical antibiotic should be prescribed.

Topical Retinoids

Retinoids are a class of molecules in the vitamin A family of molecules. The retinoids are very potent as anti-acne medications. The retinoid activation of specific RARs normalizes abnormal growth and death of cells in the sebaceous follicle; abnormal follicular cell cycles are believed to play a major role in plugging sebaceous follicles and causing comedones to form.

Retinoids are adapted as anti-acne medications in both topical and systemic forms; the systemic form will be discussed next month in the last of this three-part series on acne treatments.

The most common side effects of topical retinoids are redness, dryness, peeling and itching of skin in the areas of retinoid application. Risk for birth defects is a major side effect of systemic retinoids; the risk is much lower for topical retinoids but should be discussed with the physician when a female acne patient is pregnant or likely to become pregnant.

The topical natural and synthetic retinoids currently available as acne medications in the United States are:

Tretinoin—also known as vitamin A acid, a natural retinoid. Tretinoin is a molecule in the very large family of vitamin A-type molecules that are important for good vision, good skin quality and general good health. Tretinoin influences skin cell growth and death cycles by a cascade of events that begins with binding to RARs and ends with both direct and indirect alteration of genes that control follicular cell cycles. Topical tretinoin is available as a cream, gel or solution—a dermatologist will prescribe the form of application best for each individual patient. The maximum benefit of tretinoin’s anti-acne activity may require several weeks of treatment.

Adapalene—a synthetic retinoid applied as a gel or cream, it has potent retinoid and anti-inflammatory activity. Side effects are similar to those of tretinoin.

Tazarotene—a synthetic retinoid applied as a gel or cream, it acts on the follicular cell cycle by a biochemical pathway different from that of tretinoin. Side effects are similar to those of tretinoin.

Question of the Month

Each month we pose a question that is answered the following month. This month’s question:

Is acne that appears for the first time in adulthood different from acne that appears in adolescence?

We’ll have the answer, and a discussion of the answer, on AcneNet next month.

Answer to last month’s Question of the Month

Last month’s question was:

My doctor is prescribing a topical retinoid for my acne. He said a retinoid is a substance related to vitamin A. If the drug is related to vitamin A, shouldn’t vitamin A dietary supplements be helpful in getting rid of acne?

Dietary vitamin A has multiple health effects in the human body. Vitamin A is essential for good vision. Extreme vitamin A deficiency can result in blindness, usually accompanied by dry, scaly skin. Vitamin A overdose that far exceeds the Recommended Dietary Allowance (RDA) of 5,000 IU can have effects nearly as catastrophic. Extreme vitamin A overdose can cause the skin to blister and peel—an effect first seen in early North Pole explorers who nearly died after eating polar bear liver that has an extraordinarily high vitamin A content.

Topical retinoids are usually prescribed as a treatment for moderate to severe acne. Side effects are chiefly dermatologic, including redness, scaling and dryness of the skin, itching and burning. These side effects can usually be managed by adjustment of the amount and timing of retinoid applied to the skin. Dose adjustment must be discussed with the dermatologist who prescribed the treatment.