I got rid of most of the allergies I had since childhood by completely changing my diet and healing chronic gut damage.
Allergies are often a side effect of an overactive immune system which is being kept in high gear by something. Often that something is the fact that large particulate is making it through the gut walls and the body thinks it needs to attack it like it does a virus.
There are still a couple of things I react to, but for the most part they have settled down. I now eat organics, lots of raw plant material, as little preservatives and additives as I can possibly arrange. I stopped eating wheat which was tearing up my intestines and I didn't know it. (Milk is often a culprit, too). And I switched away from the high flash point oils in food, and most processed foods. I also started taking Peptizyde and Zyme Prime which I order from Amazon, with meals. And I did various things like lots of probiotics and aloe for a period of six months to help things heal.
Oh, and I stopped consuming soda and anything with high fructose corn syrup in it.
In the end it got rid of other problems like a pain disorder and migraines, too. But most of the things that made my eyes itch and and my sinuses swell up don't seem to bother me anymore. When oak goes nuts I still get a little reaction, but it used to be every weed, grass and tree that made me nuts.