All food allergies can work like this, as do with other immune malfunctions like celiac disease. Having the allergies/autoimmune sensitivity from birth is not a

All food allergies can work like this, as do with other immune malfunctions like celiac disease. Having the allergies/autoimmune sensitivity from birth is not as common as developing them later on. It can happen at any time in life! Most people tolerate the allergen for some period of time, and then their immune system’s response changes for reasons unknown. I have allergies to shellfish and tree nuts (plus celiac disease - gluten) diagnosed/developed later in life, along with oral allergy syndrome which sometimes causes a painful reaction to a wide range of foods, but only sometimes (depends on immune state). While I’ve never had an anaphylactic reaction, my allergist prescribed an EpiPen, saying the reactions often increase in severity suddenly with no warning.