I do the same thing -- having gone through an episode of anaphylactic shock many years ago! If my palms start to itch I start to feel panic and get all freaked out.
Story: I ate strawberries one 4th of July. A few hour later my palms were itching terribly!! by morning I was unable to walk to the bathroom -- I crawled to the bathroom so I didn't wet myself. I crawled back to the bedroom where I called my husband (now ex) and told him I needed to go to the doctor ASAP. He rushed home and took me the doc - dropping off our 4 year old at my sisters on the way. The doctor looked me over - took my BP sitting, standing and laying down. Then told my now ex --- do you want to get her to hospital or should we call an ambulance? My BP was 80/50 and I was falling into a coma. At the hospital I began to recover before they even administered Benedryl (which I'm also allergic to -- causes hives!) My BP steadily rose, but the hives remained for a couple days. To this day I don't eat fresh strawberries.
Allergic reactions are scary - and not to be taken lightly. I understand your anxiety.