What are the main causes of Melasma?

Hormonal influences are thought to be the main cause of a particular kind of hyper pigmentation known as melasma or chloasma. Darker-skinned individuals are more at risk than those with fair skin. Estrogen and progesterone sensitivity are also associated with the condition. Thyroid disease, pregnancy and stress are also thought to be causes of melasma.

Additionally, sun exposure can cause melasma because ultraviolet rays affect the cells that control pigment (melanocytes).