Melanin is a pigment that functions controlling of skin colors to protect from the sun rays. The Darker Skin carries more than a lighter skin. Our skins turned Tan color when the production of Melanin is increased. Changing of skin colors is effected by  so many reasons like the exposures of Sun Rays, chemical reactions, food poisoning, wrongly diagnosed, depression, physical stressed, grievances and sorrow, etc. 

Melanin is therefore very important in terms of maintaining skin colors  either Dark, Tan or Light. When the functioning of Melanin becomes out of order or not to the standard that needed for it's skin color maintenance will start loosing and develop patches on the body or white spots on the skin. This is called Vitiligo. Therefore, it is meant as either dysfunction or disorder of Melanin production whereas there is no specific reasons for this cause has been found yet. The disease is known autoimmune as it attacks it's own body. Vitiligo can occur across the body and could be curable on various ways. But the surety of curable percentage is not guaranteed till today. Either it can be prevented or cured but one should avoid from exposure of sun rays at any cost as it can be harmful and can create more complications.