A long time ago, where I worked in SW Oregon, the Forest Service would issue little vials of poison oak extract that you could mix with water and drink. I took a few with beer, but I don’t know whether they did any good because I have never been very sensitive to poison oak. I’m not immune, but it just doesn’t do much to me.
I’m the same way. I have eczema and in general dry skin and spend a lot of time outdoors. I can’t recall ever having poison ivy reactions.