Here's my personal
experience:
My husband and I both have asthma; mine is environmentally induced, so as an adult I have avoided the triggers to avoid the attacks (mainly animal dander). My husband's was more like yours: and certainly more severe than mine, needing two different inhalers several times a day.
However, both of us had a drastic reduction in asthma symptoms when we changed our diet to paleo/primal. We actually switched to eating this way because of my husband's diabetes (incidentally he manages it with diet and one medication--not insulin--now), and have both had noticeable health benefits, asthma reduction being just one of them.
We don't follow any one plan, but here are the things we eliminated completely: wheat, soy, corn, vegetable oils. We also avoid: all other grains, potatoes, sugar. In addition, we added cream, butter, lard and other animal fats to our daily diet.
My husband uses his inhalers rarely now. Maybe a couple times a month. I still avoid my triggers, but in unavoidable situations--like visiting inlaws--I don't get any allergy or asthma symptoms. I'm not allergic to cats now!
I can't guarantee this will work for anyone else but it worked for us, and if nothing else, it can't hurt to try, right?