i never had allergies in my life until about 3 years ago.. same exact thing, starts right away with itchiness in the mouth, then red spots, sneezing, etc.. a benadryl usually takes care of it within minutes.

the first time it happened, i almost died. did the same thing, decided to try to eat helthy, see what it's like.. bought some fruit, got home, ate some. within minutes, my whole face was swollen and red, i was shaking from the cold but pouring sweat. threw up, managed to take an advil (or something similar, i didn't even know what benadryl was back then), and passed out. it was like some shit you see in the movies, except real. next day doctor explained to me what happened, and now i carry benadryl with me. as soon as i feel the ithcing sensation or some other symptom, i take one, and it goes away.