Oranges and bananas are out for me too, because of histamine intolerance, which correlates heavily with gut issues. Sharing to help others since I wish I had known sooner!
Helped me find out I too have a histamine intolerance. No avocados or spinach!
It's primarily for IBS and identification of trigger foods, but the elimination and reintroduction steps may well help you with identifying your triggers.
https://en.m.wikipedia.org/wiki/FODMAP
They've also got a basic, but handy app.
It's done me well over the years.
I have rhinitis flare ups too - I’m not sure I’ve pinpointed exactly what flares mine up, but I most suspect guar gum / xanthan gum. Either as a trigger, or just causing thickening of mucus, which spirals into blocked noses and sinus infection issues and further rhinitis.
What really helps me is lymphatic drainage massage. There’s videos on YouTube showing you how to gently directionally massage the drainage channels to keep your sinuses clear.
This site is a pretty tight digested summary of the same elimination diet that fedup.com.au recommends