This works for me.

Run water that is about as hot as possible, but not scalding, over the affected areas. The hotter the better. It will cause the rash to itch tremendously. After 30 sec to one minute, the itch should subside. Relief usually lasts near 12 hours for me. The way I understand it is that the heat speeds up the histimine (sp?) reaction in the skin (this is why some people experience their skin itching under a very hot shower). After the 30 sec or so, the chemicals in the skin that cause this are exhausted and need time to rebuild, hence the 12 hour relief. You have to get through the itch time first, and again the hotter the better.

Stupid me decided to weed wack some brush in shorts and ended up wacking ground level poison ivy. Both legs from shorts to socks were covered about 90%. Some ended up systemic I believe as well. Using the hot water treatment I did not need calimine or other treatments for the itch. I think (highly subjective) that it helped dry it up faster as well.

As for the leaves and buds, I have contracted PI from the vine in the middle of winter. The oil is always there. Remember, PI is an alergic reaction, not an irritant, and this is why some people don't get it.