Introduction
Hyperpigmentation disorders, including melasma, are common, particularly in women,1-3 among people with darker complexions (Fitzpatrick skin types IV-VI), and especially those living in areas of intense ultraviolet (UV) radiation such as Hispanics (especially of Caribbean origin), Asians and African Americans.4-9 Melasma is not uncommon in the United States (US). In a study of 2000 dermatology patients of black origin in Washington, pigmentary problems other than vitiligo were the third most commonly-cited skin disorder.10 Among a Latino population in Dallas, prevalence of melasma was 8.8%, and 4.0% of respondents reported a previous occurrence.11 A questionnaire sent to an Arab population resident in Detroit identified a 14.5% incidence of melasma and 56.4% complained primarily of alterations in skin tone.12 It has been estimated that 50% to 70% of pregnant women in the US develop melasma.13Melasma can also lead to decreased socializing, diminished self-esteem and lower productivity, due to its psychosocial impact.14-16 Treatment can have a positive impact on quality of life.17 It is not uncommon for patients with melasma to exhibit symptoms of facial photodamage such as mottled hyperpigmentation, lentigines, fine and coarse wrinkling, tactile roughness and elastosis, and it would be advantageous to provide a skin care system that addresses both.18-21Monotherapy with hydroquinone (HQ) has been used to treat hyperpigmentation for more than 50 years. HQ is considered the gold standard. While controversy exists regarding the longterm safety of HQ, its efficacy in treating melasma, both alone and in combination with other agents is well established.22 Pigment lightening by HQ becomes evident after 5–7weeks of treatment and common adverse events (AEs) include erythema and burning.23Topical retinoids have also been shown to be effective in melasma treatment,24,25 and as well as reducing many of the clinical manifestations of photodamaged skin.26 Treatment related AEs include retinoid dermatitis characterized by burning or stinging, erythema, scaling and dry skin. Unfortunately, monotherapy, whether HQ or retinoid, can require significant treatment duration before meaningful results are evident.27 As a result, coupled with various AEs when high concentrations are applied, combination therapies have become popular.