Well.. not exactly for itchy skin per se, but it works a charm if you've got skin irritation from leakage and enzymes that may collect under the flange/wafer. The trick is to apply milk of magnesia before replacing with a new wafer. I had some pretty bad irritation, and after applying the milk of magnesia trick, the irritation went away by the next changing.
Here is where I found the trick:
It's under the heading of "Wonders of Milk of Magnesia", and provides a pretty clear step by step on how to apply it, and also why it works.
I forgot about that trick. I used to use Milk of Magnesia on a regulay basis years ago and can't remember why I stopped . Thanks for the reminder.