Cannabis is loosely related to stinging nettles (and hops plants) and I have seen a medical study which described greater than 50% of people in a test pool showing superficial (minor) allergic responses to contact with cannabis. Take from that what you will.
And as a side note, in the south of the U.S., hemp and cannabis pollen is common enough in the air (along with every other pollen) to show up as a common allergen in routine allergy testing.