I have the same question, What is the cause of my Asthma? I know that I am  
allergic to inhalants, smoke, dust, pollen, mold spores etc. Everything I 
have  tried only helps to control not cure it. The latest test is using 
probiotics  like the Swanson Blis. I am now on the second bottle and still have 
the wheeze.  I just ordered some Beta Glucan from NSC.com. Frank Jordan said 
it along with a  lung purifier, which he gives free with one order of high 
strength Beta Glucan,  has controlled his Asthma. We shall see if it helps.
Brickey