It varies from person to person. For me, if I make skin contact (hands, arms, face) with a peanut, that skin area will get inflamed and itchy. If I breathe in too much “dust” particles (basically get my nose right over a bowl of peanuts) my breathing will get tight. If I actually eat a peanut or something with peanuts in it, that’s when an anaphylactic response is triggered which is where it gets very hard to breathe, swelling and vomiting happen, etc.
I’m deathly allergic to carrots, of all things, eating them is naturally something to avoid. Several years ago I worked at a Babies r Us and someone dropped a case of carrot baby food and broke several jars. I had to be dragged out of the store and rushed to the hospital. I won’t touch them and avoid the entire produce department at stores.