The best cure for poison ivy rash that I have found is Zanfel. It's available over the counter at any drugstore, and don't let the ugly packaging deter you. I was skeptical of it at first, even after my doctor recommended it to me, but that stuff really does work. It does not stop the itching for just a few hours; it stops it for good. The first use alone is often enough to stop it completely and forever, but I sometimes have to use it again the next day or even a third day to put a final end to it. You will still have the rash, but it won't itch and it clears faster. The tubes are stupid expensive -- about $40 or so -- but I always keep it on hand. It's the only thing I have found that works AFTER the rash appears. It's also a good idea to get a prescription steroid cream for backup and for those sensitive places where you can't use Zanfel effectively. Even without the Zanfel, the cream will at least let you sleep all night without waking up scratching.