Dieffenbachia and calcium oxalate crystals
Being a low-light plant, this is one I kept when I was moving a lot because I usually rented apartments and had limited light. It was a pretty houseplant and easy to maintain.
For some reason, I eventually did not have one and recently thought about getting one again, so I decided to research the "dumb-cane" aspect of it since we have cats who tend to nibble.
I knew it had a poisonous aspect and should not be consumed but did not know that handling it could be an irritant for some and the sap could be as bad as poison ivy. Hmmm, that would make it bad to have around small children as well.
It stems from calcium oxalate crystals (raphides) that actually get worse when water is added. For ONCE I have a reason to not wash my hands. Well, not to remove the sap anyway. It seems better to wash first with witch hazel or rubbing alcohol which apparently dissolves the crystals.
Don't fall in love with dieffenbachia? But there are other plants that can cause similar reactions so if I develop a severe reaction to handling plants, I believe I would start using gloves, not give up gardening.
Maybe that is why I see folks using gloves for what I would consider normal playing in the dirt. It gives me a whole new perspective and understanding.