Fruit allergy problems?

Certain foods I eat make my throat swell up a little bit and makes it a little bit harder to breathe and swallow. It also make my teeth and inner ear itch. The foods that do it (that I've noticed) are watermelon, banana, pecans, avocado, cantaloupe, honey do, and some others. I was just wanting more information about what it is that is causing the swelling, or what foods to avoid, or if it is serious, or anything you could tel me about it.