As a fellow sufferer, I feel your pain. I used to go to work with my arms wrapped in gauze as they would literally drip. Only prednisone worked for me, and I can't imagine not being able to take it. I went thru all the allergy therapy to develop a resistance, but didn't work. I was told that once you develop a sensitivity, you become even more sensitive with each exposure.
DON'T let it go too long -- keep bugging the doctor for some relief. Non-drowsy antihistimines helped me some, and those you can get over-the-counter. I know people will treat you like typhoid Mary, but I've had many doctors tell me that the fluid from the sores is NOT a source of infection. Only exposure and contact to the actual plant toxins can spread the infection. The way it spreads on your body is because of your body's reaction to it. It always seems to get worse before it gets better.