Hi Tippy,
I can't remember if you've already tried posting in the dermatology medhelp forums.
Here's the MH expert dermatology one:
http://www.medhelp.org/forums/Dermatology/show/115
Here's the MH dermatology community:
http://www.medhelp.org/forums/Dermatology/show/65
Have you gone back to see your dermatologist yet?
There are 54 explanations for itchy rash here:
http://www.nlm.nih.gov/medlineplus/rashes.html#cat45
I tried looking for a similar picture to yours in the endless online images of skin conditions but the one I first picked didn't seem likely. Have a look, if you have time, and see if you can find a match.
Here another photo site, though I haven't found one I find easy to use. Maybe someone in the MedHelp dermatology community knows which one is the most useful:
http://www.dermnet.com/Atopic-Dermatitis-Adult-Phase/photos/1
Hubby got a severe case of poison ivy two weeks ago (weeding oh so sweet bro's garden), so I feel for you. It's hell for him and doesn't let up. He doesn't have any skin left and nothing stops him from scratching, not sleep or anything. He's in misery and would rather have been bitten alive by mosquitoes. You two would look funny in the same room.