yeah i got the same thing. except i think that mine is poison sumac, because i was walking through a marsh with my friend 2 days ago and there was really tall brush and i was wearing shorts. people say that poison sumac is more prone to grow in swampy places so i think thats what i have.
It started with about 4 black spots on my lower legs. The spots werent swollen at all and then they started to itch so i scratched them a little bit. I thought that it was just tar on my legs so i scratched one of the spots off and it bled so i left the other spots alone. Then i knew i had poison because the swollen itchy streaks started to appear on my legs....i'm using calamine lotion which seems to be working pretty good.