Originated From SnappyFingers
It depends on the sensitivity of the exposed. ex. some won't get it at all. Some will almost immediately feel the itch - see the redness and the rash is quick to follow. I have experienced this within hours or if not overnight. Hope you get better answers than this. Time to get out the calamine lotion.
Other people asked questions on similar topics, check out the answers they received:
Other people asked questions on various topics, and are still waiting for answer. Would be great if you can take a sec and answer them