I have had it bad over the years and have ended up in hospital with asthma through it, but then a Dr asked.
Had I ever tried ACUPUNCTURE so I tried it and lo and behold after a few trips to the Chinese Dr it worked, so every year I now just go for a couple of times and just take a mild tablet and no problems
When I lived in the South of Spain I used to get it real bad and it was the olive trees, now I live in Galicia in the middle of a Eucalyptus forest and hardly get even a sniff
Oh and the vaseline tip is a real good one too.