I believe the oil in the poison ivy plant can remain dormant in your skin permanently. It doesn't mean that you will have a rash but it means that it can come back.
For most of my life I was immune to poison ivy. I know I had been exposed poison ivy many times without having any affect on my skin. One year ago, I was exposed to poison ivy and did actually get a rash. The rash has not gone away for the whole year. There were times when it was less visible and didn't not itch for much of the time. But I have gotten flares ups from time to time. My reaction to the oil seems pretty minor compared to other peoples, but it is still pretty annoying.
I don't know of any way to get rid of it entirely but I am having decent luck using dish soap to stop the irritation. I believe if you have recurring cases of poison ivy then there is no real way to eliminate it completely. You have to deal with it when you get a rash and enjoy the time you don't have it. I've heard that over time the rashes should get less frequent and less severe but it is probably based on the individual's immune system.
The rash is actually your immune systems reaction to the oil. So my assumption would be that a weak immune system would react to the oil less causing a less severe rash and less itching. Just a theory, not really sure if it actually works that way.
