Postinflammatory Hyperpigmentation Treatment & Management

The treatment of postinflammatory hyperpigmentation (PIH) tends to be a difficult and prolonged process that often takes 6-12 months to achieve the desired results of depigmentation. Each of these treatment options potentially improves epidermal hypermelanosis, but none is proven effective for dermal hypermelanosis. Daily use of a broad-spectrum sunscreen (sun protection factor [SPF] 15 or greater) is an essential part of any therapeutic regimen.

A variety of topical treatments have been used to treat epidermal postinflammatory hyperpigmentation, with varying degrees of success. These agents include hydroquinone, tretinoin cream, corticosteroids, glycolic acid (GA), and azelaic acid.^[3] Lightening of hyperpigmented areas may be achieved with one of the previously named topical agents; however, a combination of topical creams and gels, chemical peels, and sunscreens may be necessary for significant improvement.^[4] They are only effective for epidermal hyperpigmentation.

Topical tretinoin 0.1% has been effective in African Americans. GA peels, in combination with tretinoin and hydroquinone, are an effective treatment of postinflammatory hyperpigmentation in dark-complexioned individuals.^[5] All-trans retinoic acid aqueous gel 0.1-0.4% may be applied concomitantly with hydroquinone–lactic acid ointment for bleaching.^{[6, 7]} After sufficient improvement of the hyperpigmentation is achieved, a corticosteroid may be applied topically with hydroquinone to promote healing. This combination of various topical therapeutic agents has been shown to be beneficial, especially on the face.

Topical azelaic acid, which has been approved for the treatment of acne vulgaris, is useful for postinflammatory hyperpigmentation.^[8] It may be desirable to use to treat acne itself for patients in whom postinflammatory hyperpigmentation tends to develop. The efficacy of tazarotene 0.1% cream for the treatment of dyschromia associated with photoaging and for acne vulgaris may also be beneficial, particularly in people with dark skin.^[9]

Early and efficacious treatment of acne in patients with dark-toned skin helps minimize pigmentary abnormalities.^[10]

Other treatment modalities include use of trichloroacetic acid and gentle cryotherapy with liquid nitrogen. Each method must be used with extreme caution to avoid necrosis or blistering of the treated skin. These 2 methods of treatment should be avoided in dark-skinned patients because of the risk of permanent depigmentation and scarring.

Pigmented makeup creams have also been successfully used to camouflage hyperpigmented skin to a hue similar to that of the surrounding unaffected skin.

More options will be available in the future. Retinaldehyde (RAL) has shown depigmenting activity, while GA decreases the excess of pigment by a wounding and reepithelization process. A combination of RAL 0.1% and GA 6% RALGA (Diacneal) in the treatment of acne vulgaris and postinflammatory hyperpigmentation was noted as successful.^[11] The peroxidase inhibitor methimazole, a noncytotoxic inhibitor of melanin production, is a possible agent for topical use in the years ahead.^[12]

The efficacy and safety of a combined treatment regimen including serial GA peels, topical azelaic acid cream, and adapalene gel in the treatment of recalcitrant melasma was evaluated in 28 patients in a prospective, randomized, controlled trial lasting 20 weeks.^[13] Those receiving chemical peels underwent serial GA peels in combination with topical azelaic acid 20% cream (twice daily) and adapalene 0.1% gel (4 times daily, applied at night). Combined treatment with serial GA peels, azelaic acid cream, and adapalene gel may be an effective and safe therapy for recalcitrant melasma.

Choi et al report that Lepidium apetalum is a potential inhibitor of hyperpigmentation caused by UV radiation.^[14]

Recent studies suggest that decapeptide-12 was 17-fold more potent than hydroquinone at inhibiting tyrosinase in vitro. .^[15] This study also showed that decapeptide-12 was not cytotoxic to melanocytes, making it a safer alternative to hydroquinone. A pilot study by Hantash and Jimenez showed that twice a day treatment for 4 months with decapeptide-12 formulated in a topical emulsion also resulted in a 50% improvement in melasma in patients who had failed 6 months of Tri-Luma therapy.^[16] The potential of decapeptide-12 as a therapeutic option for melasma was recently reviewed.^[17]

Also see Skin Lightening and Depigmenting Agents.

Fractional photothermolysis may be used to treat postinflammatory hyperpigmentation after carbon dioxide laser resurfacing.^{[18, 19]} Laser treatment may be able to address dermal pigment deposition. The 1064-nm Q-switched Nd:YAG laser with low-fluence treatment may be considered in the treatment of postinflammatory hyperpigmentation caused by procedures such as laser surgery and chemical peeling in Asian patients.^[20]

The guideline from the British Association of Dermatologist, Guidelines for topical photodynamic therapy: update,^[21] may be of interest, as may Photodynamic Therapy for the Dermatologist.