Melasma is primarily caused by an overproduction of melanin, the pigment responsible for skin color. The exact cause is not well understood, but several factors are believed to contribute to its development:
Hormonal changes during pregnancy (often referred to as the "mask of pregnancy" or chloasma) Use of oral contraceptives or hormone replacement therapy Sun exposure, which can exacerbate existing melasma Genetic predisposition Certain medications that make the skin more sensitive to sunlight
