My experience: I never had allergy issues, but after moving across the country (Alberta to Ontario), I started having a terrible time in spring and summer. I read that eating local honey can help, so I introduced it into my regular diet and since the next year I haven't needed antihistamines since. It could be a placebo effect, but I think it is worth a shot. The experience has made me much more sympathetic of people suffering allergies, I wish you luck finding relief.
I've been meaning to try that. I grew up on a farm and never had any allergies to anything, then last year moved to another state. Dear lord. Someone suggested local honey but I never got around to getting to a store that sells it. I'll have to try it this year.