I hate poison ivy and poison oak, too. When I have it, nothing helps except going to the doctor and getting a steroid prescription...except a couple of years ago Larry came home with a salve he'd gotten somewhere called Appalachian Secrets. I didn't have much hope for it but it actually worked.
A couple of years ago was the last time I'd broken out so I didn't remember where I put it. I went to several places looking for it. It didn't help that I didn't remember the name of it but I was sure I'd recognize it.
I finally found it in my drawer where I'd put it for safe keeping. I've started using it. I hope it works. It is possible that it loses its effectiveness over time...and I'm not talking months but years.
However, the address and phone number are on the tube of salve so I can call and ask where to locate it nearby.