When I showed the doctor the rash, he said he wanted to wait until we get results for my 10 yr old son. Its been a month and we are still waiting. He doesn't want me using anything but cortisone cream at this point. We don't have a dermatologist locally (she retired last year), so I will have to travel an hour and a half away to see one. That's ok though, as we will have to travel to the same location to se a pediatric GI anyway. He's still itching, but it seems to be lessening a bit.
I was prescribed with cortisone when I showed my DH to the doctor.. that was because my doc had no idea what the rash was, and didn't bother to do any testing. It did help temporarily but the blisters and the dry skin kept coming back.