perceive their disease to be worse than it has been objectively assessed.10 Conversely, successful medical management of melasma has been shown to produce feelings of confidence and positive life perceptions in patients.11
Postinflammatory hyperpigmentation (PIH), like melasma, is an extremely common acquired disorder of hyperpigmentation that follows endogenous cutaneous inflammation or external injury. Lesions can range from light brown to dark grey or black, and are distributed where the original cutaneous insult occurred. The color of the lesion is largely dictated by the depth of the pigmentary alteration, which is a consequence of the Tyndall effect of light scattering.12 PIH that is primarily epidermal is characterized by increased melanin in keratinocytes, whereas dermal PIH displays increased melanophages in the dermis.
As in the case of melasma, PIH tends to occur more commonly in those with FST III to VI,13 which is likely related to the degree of constitutive cutaneous pigmentation in affected individuals.14 These patients al so tend to exhibit a greater frequency, duration, and severity of PIH lesions. The prevalence of PIH is difficult to isolate, but can be quite high. One study found the incidence of PIH in acne patients with skin of color (SOC) to be 65.3% among African-Americans, 52.7% among Hispanics, and 47.4% among Asians.15 A survey of Arab Americans residing in Detroit, MI, found 56.4% of respondents expressing concerns about alterations in their skin tone.16
Of note, PIH may have a strong association with melasma. In a study of 400 individuals, post-acne related pigmentation was observed to be six times more likely to occur in melasma patients.17 As with melasma, PIH has also been found to negatively impact self-perception and social/emotional functioning in those afflicted.18 Designing a Therapeutic Strategy A multimodal approach is required to successfully treat melasma and PIH, though the details of a given approach are contingent upon each individual patient’s clinical presentation, general health, financial resources, and levels of compliance and reliability. Daily conscientious photoprotection should be a component of all treatment regimens, and is in most cases accompanied by the use of a topical lightening agent. Hydroquinone (HQ) is the gold standard in topical skin lightening, and when combined with tretinoin and a topical corticosteroid, its efficacy and tolerability are enhanced19 (Figure 1b). Moreover, a triple combination cream (Tri-Luma®; fluocinolone acetonide 0.01%, HQ 4%, tretinoin 0.05%) is the only topical medication that is FDA approved for the short-term treatment of moderate to severe melasma of the face.20
The choice of first-line lightening agent is also dictated by whether a patient is pregnant or breastfeeding. For example, the use of HQ as well as topical retinoids such as tretinoin and adapalene should be avoided in pregnant women due to their pregnancy category C classification, while tazarotene is pregnancy category X. The transcutaneous absorption of HQ is reported to be about 35% with subsequent secretion in breast milk, though the manifestations of potential toxicity are unclear. Nevertheless, chronic use in breastfeeding women is not recommended.21 Given that melasma will often flare during pregnancy, and likely persist during at least the initial months of breastfeeding, physicians should possess a comprehensive knowledge of topical lightening agents that can be substituted into a patient’s treatment plan during these times. There are a number of other topical agents that also work to combat hyperpigmentation via tyrosinase inhibition, antioxidation, or a combination of both (Table 1), that may be incorporated into a patient’s lightening regimen as alternatives or adjuncts to HQ or topical retinoids, when circumstances necessitate.
Several systemic agents have gained attention in recent years for their potential skin lightening ability, including tranexamic acid, polypodium leucotomos extract, and glutathione, though a reliable assessment of their safety and efficacy is limited by a dearth of large scale double-blind randomized placebo-controlled trials. Still, it may be reasonable to add some of these