When I was a child, I had such severe reactions to poison ivy that I got a series of allergy shots every year. They never worked; I always got poison ivy.
The worst case ever was the year we took a family camping trip and used poison ivy sticks to roast our marshmallows on a poison-ivy wood fire. You see, the poison ivy was growing so large and healthy at this campground that in the dark, my father mistook it for tree limbs and cut some for kindling to start the fire and some for marshmallow sticks! Ouch! I was absolutely miserable, with poison ivy all over my face and body, and enough of a reaction that I ran a fever and had to be confined to bed for a while.