I'm sure you've already looked into this, CathyA, but what about things like laundry soap allergy? I had a co-worker who had skin sensations that she finally traced to the type of laundry soap she used.
Also knew a co-worker's wife who had multiple issues (can't recall all of the symptoms) and her doc advised her to stop her habit of drinking 6 Diet Cokes a day, after which her issues mainly cleared up.
I know they say to look for the simplest answer first so forgive me if you've already checked these more obvious things..