It's funny, seasonal allergies were 1 of the few things that changing my diet hadn't resolved.

Last year I started spraying a diluted solution of CDS symptomatically up my nostrils. It seemed to relieve the symptoms & sinus inflammation but it wasn't at the worst time seasonally. 

This year I've only had 3 or 4 episodes of sneezing. Each time I got relief from the CDS & it hasn't returned the following day. A few of these episodes were after brush cutting long grass. 

Keep it in mind if it still causes you issues.