|There's already way too much folklore. And people tend to draw conclusions about cause and effect when sometimes, things just happen coincidentally. (For instance, I just read about someone who tried bleach on their rash, and because their allergic reaction spread and grew within a couple days, now they are reporting that bleach spreads poison ivy. Not True.
The only thing more maddening than getting a bad case of poison ivy/oak/sumac is the seemingly impossible task of getting rid of all the hidden urushiol in your home ... and knowing that you probably will miss some, and you'll break out again ... in a week, or a month, or a year? Fantastic.
It's the perfect hell: the irritation doesn't show up right away, and even when it does, it's usually a very minor thing, so we tend to ignore it for another day or two, especially if we have not been near any plants. Then, by the time we realize what it is, we've spent a couple days living our lives, touching darn-near everything in our house (and on the job), potentially spreading it everywhere (doorknobs, toothpaste tubes, steering wheels, microwave buttons, all that clean laundry that we just folded, etc etc etc ... good grief man, why does this stuff have to be invisible, right?)
Heck, if some guy's dog gets it on it's fur, and then the guy pets his dog, and an hour later the guy pats his buddy on the sleeve of his coat, and then I brush against that buddy's coat two days later while I'm in the grocery store --- WHAM. Another day later, I've got it ... and of course, I've got NO IDEA how. Because in the previous 4-24 hours, I've touched perhaps hundreds of things, many in public places. For some of us, it's literally impossible to identify how we got it. Those of you who always know -- you're the lucky ones.
And the kicker for some of us who are very sensitive to it is this: we get it, and it's miserable, and we get paranoid and *try* to clean everything and wash everything (which is no small matter). And somehow, we miss something. And unknowingly, we touch that thing, and we get it again ... but before we find out we got it again, we usually spread it around our newly cleaned house again.
It's just insane.
It seems bizarre to me that we don't have a medical "solution" to this yet. Only treatments -- no cures.
I get it on a regular basis, at a couple times a year; some years just a couple of minor cases, but sometimes covering most of my body, and I haven't personally been near a poison ivy/oak/sumac plant in over a decade. But that wacky oil is around here somewheres ... I'm ready to go all "young John Travolta" and be the boy in the bubble. Seriously.
There is a pretty strong medical/physical argument AGAINST the notion of a systemic reaction to urushiol. Now, I am NOT saying that our bodies aren't breaking out in hives or something similar, and perhaps as a direct result of the stress of dealing with the allergic reaction to the urushiol, but from a purely physical standpoint, urushiol probably cannot be absorbed into the bloodstream (I say probably because I'm unable to find anything which says it's impossible, ... but I am also unable to find anything regarding the transport of urushiol in blood), and even if urushiol WERE absorbed into the bloodstream, I think it's reasonable to assume that we would experience some difficulties with our internal organs as well as having rashes over large portions of our body ... and in fact, wouldn't it be fairly safe to say that a 'systemic' case would result in an ENTIRE body being covered with the allergic reaction, fairly uniformly (if the blood were carrying it around, and then delivering it to previously uninfected skin)?
I know people want to believe in systemic cases (I wanted to also, for years ... I thought my body was harboring it somewhere, and would just bring it back out for me on special occasions, haha), but I think it's much more reasonable to consider the very real possibility that it's just really easy to spread trace amounts of it around on ourselves, while we move throughout the day, and while we sleep.
Perhaps I am misguided. But by assuming a reaction is systemic, we allow ourselves to ignore the likelihood that there is still some urushiol on something in our home or workplace ... and blaming it on our blood isn't nearly as effective (for preventing further reactions) as cleaning our stuff.
And for goodness' sake, anyone who recommends eating the leaves of the plants as a way of gaining immunity should seriously be charged with reckless endangerment and wanton disregard for life, and locked up forever with no access to post anything on the internet. I'm not joking. I've read it in more than one place, and it's not even funny.
So, clean your stuff. And post a question about cleaning stuff, or moan about your case ... just don't perpetuate bogus myths, please :)