As the above comments have mentioned, cold water closes pores and hot water opens pores. Use hot water to drain it out once infected and scrub like crazy. It will hurt but I've used this method to get rid of it completely in 2 - 3 showers. You will feel and smell the oil drip from your skin. It is really sticky so either get some really strong soap or tecnu to wash it down the drain.
When it is on your skin was off with cold water within 30 minutes of contact and you will be fine. I am fairly allergic and I've pulled poison ivy up by hand on occasion using this technique with barely a trace of irritation. It was not even noticeable. Again, either use something strong like dish washing soap that cuts grease or tecnu.
The best method that I've found for pulling poison ivy is the above technique plus using two contractors bags flipped inside out to pull it out, over a period no greater than 20-ish minutes. Be sure to wash your eyes and upper arms as well because when the roots or leaves break - which they undoubtedly will while pulling - the irritant will drift to other parts of your skin and these I have found these parts of the body to be the most vulnerable.