A single 10mg Loratadine tablet per day seems to work quite well for me.
If things are really bad benedryl works very well, except it will make you drowsy. One thing I do to counteract the drowsiness is take 30mg or so of pseudoephedrine, this clears your sinuses up in addition to being a stimulant.
but 99% of the time the Loratadine works great.