I have a dandy case of poison oak on my right hand, courtesy of a brush of Badger's leash against some poison oak on a hike - I'm going to say weeks ago. I've been exposed constantly for my whole life, of course. California doesn't have poison ivy, and I don't think, "poison sumac," but it does have lots and lots and lots of poison oak.
Most of the poison oak I've seen has a reddish tone, like the picture to the left. The shrub changes throughout the year, and now in the early summer, often has little white "berries" and little waxy white flowers.
In my case, my lifelong "immunity" is gone to the point where, I thought I'd beat the stuff back, but it flared up again! The skin on my palm and underside of my fingers is so stiff that I can barely bend them. Because the skin there was tough to begin with, the blisters are deep beneath the skin. I would say it was making me mad, but there's no point. It's not going to stop me from hiking. Poison oak reactions come from one's skin coming into contact with the urushiol oil produced by these plants. Only a tiny amount is needed, and the oil will set off an extreme allergic chain reaction well-known to outdoor enthusiasts, gardeners, weeders, and those living on farms.
There is of course, a Poison Ivy, Oak and Sumac "Information Center" on the internet. On the poison ivy victim message board, it says "beware of pet fur." I am pretty sure Badger has been cross-contaminating, because this sucker has lasted at least a month so far. The good part is that it hasn't spread much past my fingers, where it obviously came from holding his leash (small patch on left hand - same deal - I switched hands when my right hand started "bothering me"). The bad part? There's still some of that urushiol oil somewhere - either I failed to wash it out of his fur, it's somewhere on my bed where I can't tell (have washed everything twice) or it's on some other common thing that I touch and hold that hasn't occurred to me yet (steering wheel of car?). That would be just sick, wouldn't it? I can't give too many helpful treatments (Sarna lotion helped me somewhat but it keeps coming back!). The Information Center linked above has more than you'd ever want to know, and some pretty horrible victim pictures.