I hate to rub it in, but I have never had a reaction even though I have been through it over and over again. My DH, however, gets covered from head to toe with blisters and usually needs steroids to help him cope. He is sensitive enough that he comes inside to wash off as soon as he comes in contact with poison ivy. Even then, he doesn't always escape a bad reaction. He feels and looks miserable, but I don't know whether is because of the blisters or "mopiness"
