Several plants are associated with photodermatitis, which in this setting is more specifically termed phytophotodermatitis. These plants contain photosensitizing chemicals called furocoumarins, a group of structurally related molecules that cause skin damage with exposure to ultraviolet light. Responsible genera include Citrus (lime), Ficus (fig), Daucus (carrot), Cymopterus (parsley), and Pastinaca (parsley), among others.
The classic presentation is cutaneous exposure to one of these plants followed by ultraviolet light exposure (eg, harvesting crops on a sunny day) resulting in a rash developing in sun-exposed areas after 24 hours
I wonder if there is anything in the above article I read this evening. Maybe look up furocoumarins???