I try not to be judgemental of others, but this sounds really strange:

What's Up With Katie's Hands?
. . . Later that day Cruise escorted his wife to their car. It was then that a photographer caught a glimpse of her ungloved hand, which had a strange dark hue. The discoloration is the result of a Scientology purification ritual called the Purification Rundown, sources told Perez Hilton. New converts to Scientology are supposed to ingest massive doses of vitamin B3, aka Niacin, which some say causes the hands to turn purple.