2 of mine have almost year-round allergies, so I feel your pain.
What do you mean by "hacking" - do you mean vomiting every day? Or do you mean like coughing/gagging?
To me, these allergies are affecting your kiddo's quality of life and I'd be looking into meds for him so he can get relief. Read more about how to approach allergies here:
http://www.yorkietalk.com/forums/die...tart-here.html