yeah... its similar to oral allergy syndrome, which is something i have- i have hayfever type allergies, and my genius body thinks tomatoes are tree and grass pollens, cos they share similar compounds, and i get the whole itchy mouth and skin thing when i eat tomatoes. its nothing more than a minor pain in the derrierre for me, but its not like that for everyone.
i think you should go back to your doctor with this, and lay off the offending stuff till then. it might just be something that is a minor inconvenience for you too, but you don't want to mess with allergies- while they might not get worse, you don't want to be munching away on bananas and then end up in anaphylactic shock, cos erm... thats not really very much fun at all.
eta: i think i recall another 'jen' on the boards having the same issue... maybe its a special 'jen-etic' thing, hehehe.