The pigment in our skin, known as melanin, is produced by the tyrosinase enzyme found in a special group of cells in our skin, melanocytes.
Occasionally, a group of melanocytes up-regulate their tyrosinase activity to produce more melanin than normal in different locations of the skin, causing dark spots and uneven skintone.
Some factors that causing abnormal up-regulation of tyrosinase activity are (1) UV-Damage, (2) Hormonal Changes (3) Inflammation and Oxidative Damage.