I'm having a brain fart on the name, but there is actually a kind of urticaria (itching) that is brought on by anxiety. I actually had it a couple of years ago during some stressful period that I don't even remember anymore. I looked in the derm and psych/neuro word books I use for work, and none of them are jumping out at me.

Got it - idiopathic urticaria.

Hopefully bumping this up with get somebody else to answer with more info. I googled it and all the hits are kind of vague.