Multiple principles underlie safe, effective PIH tx

"PIH is a serious problem for affected patients, requiring serious attention from the treating physician," says Dr. Dunwell, who is in private practice in Jamaica and lecturer, department of dermatology, University of Wales, Cardiff, Wales.

Unfortunately, PIH in dark-skinned patients can also present a therapeutic challenge. However, Dr. Dunwell outlines seven management principles that she has found helpful for optimizing success in treating this often difficult problem.

Exfoliation can be achieved with application of a variety of compounds. Topical retinoic acid is one choice, and the strength of that compound should be selected based on the physician's judgment of skin thickness and sensitivity.

"However, patients need to be carefully observed for the development of PIH secondary to retinoid-induced irritation so that the treatment can be discontinued promptly without causing further worsening of the problem being treated," Dr. Dunwell says.

Glycolic acid in a concentration of 10 percent to 20 percent can also be applied daily as an exfoliating agent by patients with skin of color, or the stratum corneum can be removed with a series of microdermabrasion treatments.

Increase epidermal turnover Increasing the epidermal cell turnover rate also promotes depigmentation by helping to remove cells containing excessive melanin granules. It too can be accomplished using microdermabrasion or with a series of chemical peels.

Appropriate peeling agents include glycolic acid 70 percent, salicylic acid 30 percent or trichloroacetic acid (TCA) 15 percent to 25 percent. In localized areas where deeper penetration is desired, a combination peel can be performed using glycolic acid 70 percent first, followed by TCA 10 percent to 35 percent.

"It may even be possible to increase the strength of TCA to 50 percent and use it safely without causing scarring as long as it is only being applied in a limited area," Dr. Dunwell says.

Decrease inflammation Suppressing inflammation is important because, in skin of color, hyperpigmentation is the sequel to inflammation. Suppression of inflammation can be achieved with short-term use of a mild to moderate corticosteroid.

"However, certain natural compounds, such as licorice extract, offer dual anti-inflammatory and depigmenting actions and are safer for long-term use," Dr. Dunwell says.

Initiate early treatment Newly deposited pigment is much easier to remove than longstanding PIH, and so, for best results, treatment should be started in the early stages of inflammation rather than delayed.

Suppress melanocyte activity Suppression of melanocyte activity and prevention of melanogenesis can be accomplished using a variety of depigmenting agents (see principle 6). However, sun avoidance and sun protection with routine application of a broad-spectrum sunblock are also key elements of this treatment principle.

"Use of a sunblock is critical because the melanocytes in persons with skin of color are very active, and many of these individuals live in sunny regions where they are exposed to constant UV-induced stimulation of the pigment cells," Dr. Dunwell says.

Patients should also be watched for any irritant or allergic reaction to sunblocks that can lead to hyperpigmentation, and a physical blocker rather than a chemical-based product is preferred for individuals with very sensitive skin.

Dr. Dunwell also advises that patients be cautioned against rubbing the sunblock or the depigmenting agent into the skin.

"Some patients may think that more aggressive application of the depigmenting agent might improve its efficacy and hasten response. However, the friction effect from the rubbing can actually worsen their condition," Dr. Dunwell explains.