It sounds, to me, like you have some natural chemical reactions that might be at the root of your ongoing infections.
Umpteen years ago, my doctor told me that my system was highly acidic and to minimize my intake of acidic foods. This meant cutting back on both foods I seemed to stay shy of, anyway, and those I absolutely loved, like citrus, tomatoes, even strawberries. To my system, these foods trigger the burning sensations. Not fun.
Chemical reactions are also caused by contact with substances that can trigger responses. Again, for me, certain fibers, for example, latex.
Oh, and I also want to add: I'm sensitive to my own sweat, go figure!
Have you ever been tested for your body's pH factor? Just a thought.