INTRODUCTION
Melasma is a photoaging condition with a typical clinical and histological pattern under a genetic and epigenetic context. It is characterized by hyperpigmentation in sun-exposed areas of the skin, typically occurring on the face, with a higher prevalence in females and darker skin types.1 In this condition, a complex interaction is generated between melanocytes, fibroblasts, keratinocytes, and some immunological cells (mast cells) due to oxidative stress and the inflammatory pattern secondary to exposure to various forms of electromagnetic radiation.2
The prevalence varies depending on skin phototype, intensity of sun exposure, or ethnicity.3 It ranges between 1% and 50%.1 However, studies have reported higher prevalence among pigmented phototypes such as is found among patients of Asian, Indian, Mediterranean, and African descent.3 In America, it is more common between Latins who live in tropical areas, higher altitudes, and are more exposed to electromagnetic radiation.3 Normally, the age of onset is between 30 and 40 years.1 Lesions consist of reticulated hyperpigmented macules and patches that can be categorized by both the location and depth of involvement.4 Melasma occurs predominantly in centrofacial, malar, and mandibular areas of the face, but also can be seen on the rest of the body like the neck, chest, and forearms.5 It also can be categorized by the depth of involvement with four categories; epidermal, dermal, mixed, and indeterminate.3
The mayor etiologic factors include genetic predisposition, electromagnetic radiation such as ultraviolet energy, visible light and infrared light, pregnancy, contamination that has airborne particles and aromatic hydrocarbons, hormonal influences (mainly proopiomelanocortins, estrogens, and progestogens), prescription drugs, infections, and skin aging.4
The prevalence varies depending on skin phototype, intensity of sun exposure, or ethnicity.3 It ranges between 1% and 50%.1 However, studies have reported higher prevalence among pigmented phototypes such as is found among patients of Asian, Indian, Mediterranean, and African descent.3 In America, it is more common between Latins who live in tropical areas, higher altitudes, and are more exposed to electromagnetic radiation.3 Normally, the age of onset is between 30 and 40 years.1 Lesions consist of reticulated hyperpigmented macules and patches that can be categorized by both the location and depth of involvement.4 Melasma occurs predominantly in centrofacial, malar, and mandibular areas of the face, but also can be seen on the rest of the body like the neck, chest, and forearms.5 It also can be categorized by the depth of involvement with four categories; epidermal, dermal, mixed, and indeterminate.3
The mayor etiologic factors include genetic predisposition, electromagnetic radiation such as ultraviolet energy, visible light and infrared light, pregnancy, contamination that has airborne particles and aromatic hydrocarbons, hormonal influences (mainly proopiomelanocortins, estrogens, and progestogens), prescription drugs, infections, and skin aging.4
