either a real allergy exists that could be causing the issue .... or, a pinched set of nerves in the neck can cause the same reaction... many people mis-diagnose sinus issues as allergies when the actual issue is compressed nerves in the C3-C4 area
its amazing how a pinched nerve can cause severe swelling of the sinus and create pain behind the eyes... and almost debilitating pain but not feel the real source in the neck....
ever wonder why your hand goes dead when you wack your elbow??