Melasma is one of the most common hyperpigmen- tary disorders; it is a frequently acquired disturbance characterized by symmetric, hyperpigmented patch- es with an irregular outline that occurs most commonly on the face. It is most prevalent among young to middle-aged women who are Hispanic, Asian, or of African or Middle Eastern descent.
The hypermelanosis affects the upper lip, cheeks, forehead, and chin and becomes more apparent following sun exposure.1,2 Le- sions fade during winter months, and they frequently first appear or are accentuated following exposure to UV irradiation during pregnancy. In light pigmented individuals, “the mask of preg- nancy” often diminishes or disappears after parturition, whereas it may persist in women with more darkly pigmented skin.
Although the exact pathogenesis of melasma is unknown, it is hypothesized that following exposure to UV irradiation, hyper- functional melanocytes within involved skin produce increased amounts of melanin as compared to uninvolved skin.3,4
Melasma is an important cosmetic problem that can cause serious emotional and psychological problems especially in Asian females.5
A lot of topical medications have been used for treatment of melas- ma. They are divided into two major groups: 1) Phenol derivatives: hydroquinone, which may be used as a monotherapy or in combi- nation with Tretinoin (0.05–0.1%) and a corticosteroid (class V–VII).
2) Nonphenolic lightening agents: glycolic acid, kojic acid (a thy- rosinase inhibitor), and azelaic acid (15–20%), also an inhibitor of thyrosinase.
Nowadays chemical peelings are generally used in treatment of melasma, and the standard one is glycolic acid 70% (GA 70%), a superficial chemical peel and one of the alpha-hydroxy acids (AHAs) frequently used in low concentrations as an over-the- counter preparation for daily use. Weekly or biweekly application of GA 40–70% have been used most often for acne, mild photo- aging, and melasma.6-10
Tretinoin in low concentrations (up to 0.1%) is also used as a topical lightening agent for melasma. Recently, Tretinoin in higher concentrations (1%) has been used as a peeling agent for treatment of melasma and seems to be very effective ac- cording to some users.11,12