The first thing you need to know about the skin color is that it is made up of three main components: melanin, carotene and blood vessels. Each of these components has a great role in establishing the skin color of an individual. Thus, the presence of melanin gives skin a darker tint, the carotene is responsible for offering the skin that yellowish color specific to the people with Asian ancestors, while the vessels which can be seen through the skin usually give it the reddish or pinkish nuance. These components in most of the cases combine, thus resulting the individual's skin color.

As you could probably guess, those dark patches of skin or brown spots you have to deal with are mostly due to the increased production of melanin. This substance, responsible with skin darkening has also the role of preventing the UV rays coming from the sun to affect or damage in any way the layers of skin or the sweat glands. Thus, in case of exposure to sun, the amount of melanin is increasing, the so called tan appearing. When the melanin is no longer able to counterbalance the effects of sun, the sunburns and skin damages appear. Also, because patches of skin respond differently to sun's aggression, dark patches or brown spots that will remain permanently on your skin may appear.