If you get a poison Ivy rash, place affected area under tap with warm water in a sink or shower. Slowly increase the warmth of the water until it is as hot as you can stand it for as long as you can stand it. Pat dry and coat with aloe vera gel or good lotion.
This will temporarily take the itch out for at least an hour or two. Repeat the process after it starts to itch again. The rash will dry up much sooner and not spread.