My hubby had a horrible case of poison ivy about a year ago. Nothing seemed to help - he was miserable. One thing he said that soothed it a little bit was taking baths in the Aveeno oatmeal bath stuff. It comes in packets. He said don't take hot baths.
For him it was the Prednisone that finally helped but I know you said you can't take that.
I feel sorry for you.