What's an allergic reaction? Is mcs real?

Inflammatory rxn. An allergic reaction is the body's defense against an agent it considers harmful or toxic to the body. Most allergic reactions start with food allergies that are undiagnosed and "rev up" the immune system leading to multiple other reactions to environmental items as in mcs. First firgure out what's wrong with the gut and fix it and the immune system will settle down and others will lessen/go away.