Mattress Allergy?

So, we are just posting this out into blog world to find some answers. We think Kameryn may be allergic to something in her room which is then causing her asthma attacks. Brandon and I had an epiphany last night when we realized Kameryn always and only had coughing attacks at night when she was put in her own bed. (Which, by the way, may be why she hates her bed. Funny story, yesterday I moved her mattress out of her room so I could get to some of the bins under it. She walked into the room and said "Where's my bed?" I responded "You told me you didn't like it, so I got rid of it." -reverse psychology - "Oh, ok" -reverse psychology denied!)
We got to thinking, I wonder if there is a correlation. Her coughing started when we got the mattress, so maybe that is it. We don't even know if one can be allergic to their mattress. But we have been told that allergens can cause asthma attacks (which is why we replaced her pillow and comforter a while back)
Now, we also realize that Kameryn occasionally has coughing fits at night when she isn't in her bed. But, when we can get her to sleep in her bed she ALWAYS has them. Of course it could be an allergen in her room instead of her bed. We are just starting our "investigation" so we haven't ruled anything out yet.
Anyway, we would appreciate if you would leave comments if you know anything about this.