My seven year old daughter has a perceived peanut allergy, based on one experience where she ate a candy bar, then threw up. She refuses all peanut products.
We have explained the idea of coincidence to her and tested this theory by slipping peanut products into her diet with no ill effects. We believe this is self-induced.
Since there are no ill effects, we don't plan a trip to the doctor for tests.
I'll check this thread later when I get home.
Sometimes it's an associated thing ~ like the apple peel business. The substance you are reacting to is in the peel. With candy bars there could be almost anything in there. It's natural to avoid foods that caused you serious distress.
I, myself, avoided turkey for several years after a wild one hit my car going 70 MPH in West Virginia.
It was 100 degrees that day and I foolishly tried to wash off the car.