Dark skin is called Hyper-pigmentation. It is a condition in which excess melanin is produced by the melanocytes in the skin, resulting in a blotchy appearance. If the melanocyte is exposed to a source of trigger over and over again, it may become permanently damaged and remain in an overactive mode. This means that the cell will always produce excess melanin, even when the trigger is removed.
The appearance of hyper pigmentation or brown spots on the face is one of the earliest forms of skin ageing. Research shows that there are 2 distinct types of ageing. Ageing caused by the genes we inherit is called intrinsic ageing. The other type is called extrinsic ageing and is caused by environmental factors like sun, pollutants etc. Melasma, Freckles, Lentigines or age spots, spider veins, fine wrinkles, blotchy complexion are all signs of skin ageing. They are collectively called Photo-ageing. They may slowly evolve over years or develop suddenly. With repeated exposure, the skin loses its ability to repair and the damage accumulates.