Vitiligo is a condition in which white patches develop on the skin. Any location on the body can be affected, and most people with vitiligo have white patches on many areas.
The skin doesn't have its characteristic color because it has lost its melanin. For some reason, the pigment-forming cells known as melanocytes have been destroyed.
We don't know exactly why this happens. It might be an autoimmune condition, where your body's defenses turn on your own cells instead of attacking invading germs.
Although vitiligo affects all races equally, it's more noticeable in dark-skinned people.