Pigmentation can be defined as the coloration of the skin. Your skin gets its color from a pigment called melanin.
When skin cells are healthy, the skin will appear normal and even. However, when skin cells become damaged or unhealthy, extra melanin is produced to help protect your skin. Alternatively, the cells that produce pigment can be damaged, which prevents melanin production. As a result, parts of your skin may turn lighter (hypopigmentation) or darker (hyperpigmentation), both of which are recognizable skin conditions.
Some pigmentation disorders affect just patches of skin. Others affect your entire body.
Exposure to the sun
Trauma to the skin (such as burns or as a result of spots and picking)