I looked at the picture posted at the top of the posts, and it does not look like poison ivy, oak or sumac to me.
The white bumps are unusual looking. Usually the blisters that form from poison ivy/oak do not look like that. They are flatter.
I went to the book I wrote, "The Poison Oak & Poison Ivy Survival Guide," and the only one of different rashes I noted in the book that look like this is chiggers. They are not found in the western third of the U.S. The white center is hardened, and itches ferociously. Poison ivy or poison oak rashes do not have hardened white heads.