Some people are sensitive to different pollens. Your body is obviously sensitive to the pollen of the siring tree but probably not to grass pollens. On the other hand some people will be sensitive to grass pollen but not that of the siring tree. I don't know how common the siring tree is with you but the only real remedy is to stay away from it in flowering season.

As Bulbaholic says allergic reactions to things like pollen, cats can upset some and not others, I am sensitive to Lillies I sneeze if the pollen is about so I dont have them in the house if I have to I take remove the pollen tips which seems to stop the reaction.

Have a great cristmas and a happy new year see next year, and drive safely to your all
love xavia

Happy christmas to you Xavia take care.