For me, dairy and sugar (maybe it was corn syrup) was more of a 'sinus clogger'. But I didn't notice it with gluten.
Last Sunday I ate some corn off of the cob raw and it seemed fine, sometimes in the summer I'll cut the kernels off 3 cobs and put it in a high speed blender with a cup of water and a dozen brazil nuts to make a raw soup, I'm guessing at the measurements so it might have been more or less water with some sea salt and spices added. I think I added some tumeric to make it more yellowish or orange color.
There is a stash of peeled frozen bananas in my freezer to sweeten smoothies so I don't really use sugar, but I probably use more than enough sweet fruits in recipes. Dates are quite sweetening in smoothies and puddings and granola bars too.
Actually, my sinuses are much clearer over the past 4 years and maybe that's why I've been much healthier, it seems like I don't have to do regular exercise or gym work to stay fit. Just a half hour of basic yoga in the mornings, 2 or 3 jogs a month, a few bike rides or hikes or kayak trips, it doesn't seem like a battle anymore, just an easy going experience. I go to a gym about once a month.
At 63 years of age, I rode my riding lawn mower for 2 hours today and was less stiff than 5 years ago. Cool. Except for the tick trying to bite my palm. Oh well, that's life, Gil.