My son has "seasonal" allergies. Unfortunately he seems to be allergic to something for each season. We're in GA, so there's always some kind of pollen to bother him.
We started out treating with saline as well. But after repeated double ear infections, sinus infections so severe he had green gunk oozing out of his eyes and several upper respiratory/wheezing issues... we now have him on Zyrtec. We've been quite pleased with it. We have him on it at the recommendation of our ped, who is not the type to medicate just because.
We also have a nebulizer machine for when the wheezing gets bad. (My ped doesn't want to diagnose him with asthma at this point but she said if he doesn't outgrow it he'll probably be diagnosed with allergy induced asthma.)
Just wanted to offer you a bit of moral support and mention that in the south "seasonal" allergies can be all year round.
A few things that help him - menthol in the bathwater, a humidifier in his room (cool mist of course), propping his mattress up a little and giving him vitamin C daily.