Additional adjunctive therapies include chemical peels, lasers, and intense pulsed light.22-25 Though these treatments may enhance the results yielded by photoprotection and topical and/or systemic therapy, they should never be used as first-line monotherapy due to the risk of PIH, especially in SOC. Their use requires careful counseling to ensure that patients understand that these physical modalities will at best provide some temporary improvement in the appearance of melasma, and that relapse is possible despite the high financial burden these treatments might carry. It is reasonable to anticipate better outcomes in the treatment of PIH, provided that the initial inflammatory event or cutaneous injury that caused the dyspigmentation has been fully quelled. Only reliable, compliant patients should be selected for these procedures, as pre- and post-treatment regimens require a high degree of adherence in order to prevent adverse effects such as PIH, scarring, and skin infection.
When designing a treatment approach for a given patient, clinicians should remind themselves to consider the differential diagnosis of facial hyperpigmentation (Table 2). Conditions that mimic melasma may require a therapeutic redesign, and may also affect the manner in which a patient is counseled on treatment options, cost, and outcome expectations. All discussions about treatment should first be preceded by a thorough history that inquires about past dermatologic conditions, recent cutaneous exposures, medical comorbidities, and medications (including over the counter supplements and analgesics, or other remedies that may have been purchased from the Internet or when traveling abroad), in order to first rule out other potential causes of non-melasma facial hyperpigmentation.
This review will highlight established and emerging therapies for the medical management of melasma and PIH, with an emphasis on their mechanisms, protocols, and outcomes.
Consistent, rigorous, daily photoprotection is the foundation of all active and maintenance treatment regimens for melasma and PIH. Ultraviolet (UV) light is known to exacerbate both conditions, while the regular aggressive use of topical sunscreen alone has been conversely demonstrated to improve hyperpigmentation in both pregnant women and non-pregnant SOC patients.26,27 Patients should be instructed to apply a sunscreen with broad spectrum UV protection with a sun protection factor (SPF) of ≥ 30, as part of their daily morning routine, as well as every two hours throughout the day depending on the nature and location of their activities. Some have advocated for the use of sunscreens with SPF ≥ 70, as they have been shown to add clinical benefits when applied in volumes typically utilized by consumers.28
Visible light (400–700nm) has been shown to induce pronounced and sustained pigmentation in FST IV–VI, and may exacerbate melasma.29,30 It has more recently been found that OPN3, a G-protein coupled receptor that serves as a visible blue light sensor on melanocytes, promotes melanogenesis through its involvement in a signaling cascade that begins with visible light exposure, and culminates in the increased expression of tyrosinase and dopachrome tautomerase.31 While physical blocking sunscreens that contain nonmicronized titanium dioxide and zinc oxide confer protection against both UV and visible light, the white to gray sheen they often create on SOC is cosmetically unacceptable to many individuals. Iron oxide is capable of acting as a UV-visible light filter, while providing better cosmesis for SOC. UV-visible light sunscreens containing iron oxide have been shown in various studies to improve Melasma Activity and Severity Index (MASI) scores.32,33
Patients should be counseled on multiple photoprotective measures, given their innate value as therapeutic adjuncts, and the challenge to compliance that frequent topical sunscreen application presents. These measures include avoiding dias