What Causes A Rash With Blisters On Arms And Foot?

I have cll stage 0 . I am 61, in othrwise good health and was wondering if the rash i have whic h begin with small red pimples and on a few places(underside of forearm) has blisters that burst and itches. The internist said it is poison ivy(i was gardening) but i am not sure if it is cll caused. it is on both arms and a tiny bit on the top of my foot and between my fingers.