I used to suffer terribly with perennial allergenic rhinitis. Like hay fever but had it all the time. One cetirizine usually sorts it out but I occasionally used a steroid nasal spray as well. Recently, rather than the nasal spray, I have used a seawater spray to wash out the nostrils in times of high pollen counts and that seems to work as well.

One odd one I heard recently was a man who claims stinging himself with nettles once a week stops his symptoms. Dunno if I fancy trying it myself though :-O