I somehow got poison ivy on my forearm a few years back and the whole area was totally free of RSD until it cleared up. Unfortunately I'm pretty immune to poison ivy and subsequent attempts to get it again have failed.

I tried the capsaisin but the relief was temporary for me and was outweighed by the discomfort. Perhaps it's worth another try.

The active ingredient in poison ivy is urushiol oil. This oil is on all parts of the plant I believe. I could have made a fortune on the oil since I had access to a substantial amount and it's not available on the market.

The RSD gets better when I get diverticulitis too. The doctor said this isn't unusual.

Some people are very sensitive to poison ivy and I wouldn't recommend intentional contact. Poison ivy can be very dangerous and there are several fatalities every year. Usually these are caused by internal exposure by breathing the fumes from fires or the like.