A question for you experienced moms out there!

Ok all you experienced moms out there! I have a question: Savannah has been on rice cereal for about a month and has done just fine with it. A few weeks ago, I gave her some bananas (beechnut brand) and her face broke out in red blotches, mostly under her eyes. I tried again the next day with the same brand, and the same thing happened. A few days later, I mashed up my own fresh banana in a food processor, mixed it with formula, and she did just fine. No blotches. I decided to lay off the fruit for a while, then tonight, decided to 
 her poor face broke out in blotches again! As soon as I stopped feeding her, it almost instantly went away. I called the nurse, and she said it may be a food allergy, but I don't think it is, seeing as it was two different types a fruit, and Savy did fine with a fresh banana, AND the blotches were only on her face, specifically around her eyes, and no where else on her body and didn't seem to be affecting her breathing or swallowing in any way, and she seemed perfectly fine in every way (besides being mad that I stopped feeding her yummy peaches.) Any one else ever have this problem and possibly know what it may be?