I have a few teeny-tiny (as in, pencil-point/eraser sized) vitiligo spots. They are so small that they're hardly noticeable. I also have Addison's disease and pernicious anemia, so I don't know it they are related to diabetes, Addison's, pernicious anemia, or none/some/all.
My SIL is not diabetic, but she has pretty bad vitiligo. She avoids the sun as much as possible. She was going to get laser treatments on it for a while, but I think she may have stopped doing those.