I had a mild case of asthma as well as terrible allergies throughout most of my life. I would get sick multiple times a year. After I went strict Paleo over 5 years ago my allergies were gone and I haven't been sick once. I no longer get the asthma related symptoms either. In my opinion my allergies and mucous formation was caused by dairy intolerance. When I eat out and have a dish with conventional cheese it always causes some sort of inflammation. I would consider trying to go strict Paleo by omitting all dairy and wheat products and see if that helps. Then you can add things back in to test to see which was more inflammatory.
"If man made it, don't eat it" - Jack Lallane
People say I am on a "crazy" diet. What is so crazy about eating veggies, fruits, seafood and organ meats? Just because I don't eat whole wheat and processed food doesn't make my diet "crazy". Maybe everyone else with a SAD are the "crazy" ones for putting that junk in their system.