Is it considered unhealthy to eat certain fruits and vegetables if i'm mildly allergic to them?

Oral allergy: If your symptoms are limited to the mouth and you have spring seasonal nasal allergies, you are suffering from oral allergy. This is a cross reaction between fresh fruits and tree pollen. If you take antihistamines prior to eating fresh fruits it attenuates the reaction. Your best long term relief is to get allergy shots for tree pollen and your oral reactions fade with time, see an allergist.