I came down with a nasty rash that looked like the effects of Urushiol oil. I think I finally tracked down the culprit: some Poison Ivy in my yard.
Can someone take a look at the attached pictures and tell me if it looks like it?
The vine has clusters of three leaves, the center one has a longer stem than the middle one. The leaves have two small edges. The younger leaves have a red tint.
This is in northern Illinois (Wadsworth); climate zone 5.