I use alcohol and disposable tissues to rub off the poison ivy poison.
It gets worse for a few hours and is gone the next day.
This may not work for everybody.
I just stay on the sidewalk. =)
A nurse I knew worked at a summer camp, and the newbie camp helper was letting all the kids pick big bunches of poison ivy as part of a leaf project. When the nurse saw it, she ran to the kitchen for a bottle of dish detergent, ordered every kid into the lake, and had them scrub their affected parts with dish soap. Not one kid developed blisters.
My friend read on the internet that yeast infection medicine, the kind you get in the feminine products aisle, works on bad poison ivy, so he tried it. He reported that it cleared it up better than any prescription he was ever given.