I have been struggling with this for last 5-6 years, so this is the list of things that didn't work, and the ones that did.
By the way, I absolutely refuse to use the "conventional" remedies, such as nasal sprays, antihistamines, etc. (I am not going to get on a soap box about the reasons why, other than pointing to the current criminal state of what we call "health care", and, just for the record, I haven't been to "medical" doctor for over 10 years now).
What other people suggest (worked for them, but not for me):
: eating small amount of local honey about 1-2 months prior to the outbreak (homeopathic approach, that is supposed to build immunity over period of time)- didn't work for me at all.
: homeopathic droplets of cedar sold in local stores
(I love homeopathy, and use it a lot, but in this instance it didn't produce any effects)
: Certain homeopathic products (single remedies, such as Alium cepa, or anything, that is designed to work with runny nose and watery eyes, and sneezing) work to SOME degree
: one season I discovered bee pollen (sold in health food section in refrigerator), it totally made ALL symptoms go away (I had to take it continuously, and ate large amounts of it over the period of time).
The next year, however, (I guess maybe I'd OD'ed on that stuff and developed some intolerance), I experienced severe stomach cramps upon ingesting just miniscule amounts and had to stop. So there went that one.
Since then I experienced somewhat similar relief (shortlived, but worth it) with just taking vitamin B (B12, I believe) which didn't produce the awfull stomach pains. Also had to be taken continuously.
: So this year, what so far seems to be working just fine, was - I did several liver flushes, that you can read about on this web site, (make sure you also check out the Liver Flush Forum ). Mine produced a lot of stones each time (total of three times). Relieving the liver of at least some of the gunk, that it has to deal with on daily basis helps tremendously.
I also did The Master Cleanse fast for 15 days, which I'm sure helped quite a bit (see also this web site).
: The last thing (it is hard to tell which one DID it) was, I have been eating continuously the cedar berries (we have a juniper tree in the front yard, what a blessing and curse at the same time!!!), so ever since the berries appeared, I have been eating couple of them at a time throughout the day every day, which is also supposed to build immunity to the pollen.
: By the way, one thing, that has always worked in the beginning and the final stages of the outbreak (not when the pollen count is high) is drinking my own pee, which is replete with the body's own natural antibodies to whatever is going on and assaulting it at the moment.
(before you get too grossed out, do some serious research on the topic, it is quite fascinating and enlightening, urine being among other things the most clean, distilled liquid, that your body produces. But if it sounds too much, you can skip that one, it took me some time to actually "get into that".)
So while most of these things you sort of have to plan at least little bit ahead, probably doing the liver flush, and at least a modified fast would be something you can do right now, and of course it is never too late to eat the juniper berries.
Hope this will help at least some, let me know of your progress.