I am ALWAYS getting into poison ivy or oak. Miserable stuff. I was looking up relief for the itching online, and believe it or not, I found one that actually worked, and it's nothing more than a hot shower.
You run the water as hot as you can possibly stand. The burning and itching will become unbearable as it reacts to the hot water for a moment or so, but afterwords . . . complete relief. By complete relief, I mean I feel NO itching for about four hours. Once I start to itch again I just rinse the affected areas again. Histamine is the chemical that causes a reaction, an itch, in a person with poison ivy, bug bites, etc. When you rinse your skin with hot water, the histamine rushes to the site and it temporarily itches more. At a point, the histamine flushes from the site, and it doesn't itch again until the histamine has a chance to build back up.