I've had skin reaction to ERC when sawdust got under my wristwatch. No problem otherwise. A way to test for skin sensitivity to specific wood is to put a bit of sawdust under a bandaid applied to the skin on the underside of your forearm.

I can be affected by Cocobolo dust if I don't keep it off or wash it off my skin. The absolute worst wood for me is something that was labeled Borneo Rosewood.

Reactions to breathing dust is different and I understand it gets worse with exposure. I know of two people who developed such sensitivities they had to give up working with any type of wood. One guy couldn't even go into his detached shop building even after it was professionally cleaned several times - he sold the house and had a new one built. Told me he was taking up metal turning/machining. I use a good cyclone and industrial respirators to try to keep fine dust out of my lungs.