sprinkaan

I know there are two types of asthma - allergic and non allergic...
When it comes to triggers for non-atopic asthma, drugs and chemials like preservatives are possible triggers..

From personal experience, I get bronchospasms after only a few mouth-fulls of fruit juice preserved with e.g. Sodium Benzoate. This is usually an immediate reaction. How is this not allergic??

I don't know if my confusion is because of my lack of immunology knowledge, but if you have any ideas..?