Just FTR Lyme joined on the day of that post and has posted exactly one time. I don’t know about levels of evidence but his is not only an anecdote but it’s an unconfirmed anecdote. As evidence, I would rank it with alien abduction accounts.
I’m not a doctor, but I do have more allergies than any three people collectively should have. I’m going to guess he gave you some sort of steroid shot, maybe something like prednisone which pretty reliably tamps down allergic reactions. But, as I said, I’m not a doctor and I wasn’t there, it’s just a wild-assed guess.
Just how do you think they test new drugs? They do pretty much that - ask for volunteers to take something that may well be poison and monitor the results.
Anyhow - QtM wasn’t advocating anyone actually doing that, just saying that that is definitive proof of the effectiveness (or not) of a proposed medical treatment.
Despite what I said about being a walking collection of allergies, poison ivy is, in fact, one of the things I DON’T react to (so far). This is actually a family trait, most of the people I’m related to don’t readily react to it, either… except for that one uncle who never, ever had a problem with it until that one day when he was in his 50’s when he had an epically bad reaction, spent a couple weeks in the hospital unable to eat, drink, and barely able to breathe. Yes, you can suddenly develop a sensitivity to it, without warning.
Which is why, when my landlord occasionally employs me to rid a location of the “three leaf bitch” (great name) I don’t get stupid. I cover up my body, after I’m done the clothes, including gloves, are bagged until I get get them properly washed and decontaminated, and all tools used in the extirpation are thoroughly cleaned as well. Sure, my immunity might last a lifetime, but it might not. It’s more likely to last, though, if I don’t keep testing it.
This is particularly important as my landlord is highly sensitive to the stuff, to the point if, after I do a clearance operation, I merely sit in his truck he can (and has) subsequently get the rash from the traces of oil I leave behind while doing such a thing (this is also why a drop cloth is spread on my truck seat if I need to transport myself to a jobsite, and I take myself in my truck instead of going with the landlord). When he does get it he usually winds up on a course of steroids. It’s his only allergy. Let’s just say he’s got some empathy for why I won’t touch tomato plants (which give me quite a nice rash due to my allergy to them). He didn’t use to react to poison ivy, but developed the sensitivity after adulthood.
Firsthand a couple years ago, I watched a deer eat some poison ivy with no hesitation whatsoever. Myself eating it is a completely different story, if I see it I break out.