I wish I had good news for you but just like Jim, I seem to be striking out. Is it possible you are actually not coming in contact with urushiol oil (the toxin in poison ivy, oak, sumac)? Could it be that you are experiencing a photosensitivity? In all medical references I've found to date, there is mention of symptoms with allergic contact dermatitis (ACD) which include a burning sensation. BUT with ACD one of the primary symptoms is itching.

Anyway, back to the photosensitivity. I found a pretty good site which explains photosensitivity and various factors which can cause photosensitivity. Here is the info: Pharmacist info website. I have experienced personally photosensitivity when using certain sun tan lotions. That was not fun - it was sort of a cross between a bad sunburn and a nasty rash.

Otherwise, I've come up empty on my searching. Perhaps someone else will have more info.