Melasma treatments continue to proliferate but long-lasting results remain out of reach.
Melasma can be categorized according to clinical patterns and histopathology, or depth of pigment in the skin.
The three typical patterns are centrofacial, involving the cheeks, forehead, upper lip, nose and chin; malar, involving the cheeks and nose; and mandibular, involving the lower sides of the face.
Melasma is an epidermal or dermal disease; however, the majority of cases involve pigment in all skin layers. Determining the depth of pigment deposits can be very difficult.
In the epidermal form, characterized by brown color, melanin is found in the basal and suprabasal layers.
In dermal melasma, which appears more blue-gray, melanin is found in the superficial and deep perivascular melanosomes. The epidermal form is easier to treat and more amenable to topical therapy, while dermal or mixed melasma is more resistant to treatment.