It's not just a response, it's an over response. When we say people have "an allergy" we do not mean that they are uniquely vulnerable to an irritant and their body must compensate for it, we mean their body unnecessarily responds to a benign marker.
I was diagnosed with chronic heavy metal poisoning [0][1]. I had developed almst asthma-like pollen allergy after an event that very likely contributed quite a bit all at once. Over the years I also got allergic to cats. Everything is completely gone now after years of chelation. The creation of additional "outflow" surely must have helped get the stuff out from the system overwhelmed by amounts it could not handle using its normal methods.
A tiny bit of my story, pieces of it posted on several occasions:
There are plenty of diseases which our body over-responds to. Colitis is one great example of the body basically attacking its own colon via it's immune system for no known scientific reason. And there are plenty of others.
Typically the bodies default response to everything, real of not, is inflammation. Which is the primary symptom of allergies. Which also happens to be the symptom most responsible for the popular diseases for which there is no rational/clear response for such a potentially dangerous over-reaction - other than unlucky genetics.
