He had vitiligo. It causes your skin to lose pigment over time in patches. Some think he started wearing a glove on one hand back in the 80’s to hide it. Some people who have vitiligo cover it up with makeup until it becomes unmanageable. Then they give up and go White. I read years ago that people with vitiligo likely have celiac disease and their vitiligo is caused by the inflammation they get when they eat wheat.