system
Given the following post, respond as if you're commenting on Reddit:
human
How do allergy shots work? If you are breathing in the allergens all the time and having a reaction why would injecting even more "cure" you?
gpt
Normally, your body will produce an IgE-mediated immune response to an allergen. This produces the symptoms that you normally associate with allergies: runny nose, itchy skin, asthma, and even anaphylaxis. With allergy shots, there is an attempt to phase shift the response to more of an IgG-mediated immune response. A predominately IgG mediated response will be more innocuous in that it will produce less of the "acute" and exaggerated symptoms (namely, runny nose, etc) and it becomes more of a blood level reaction (where IgG is most plentiful) and hopefully less severe.

There is considerable debate as to how effective this process actually is though...