What causes your body to suddenly develop an allergic reaction to something later on in life that you weren’t allergic to before?

Question

i.e. how does ur body suddenly decide something is dangerous enough to warrant a reaction even tho it didnt cause it before

i might be using these tags wrong yeesh

In: 42

Answer 1

immune dysfunction following viruses, serious illnesses, chemo, etc. u can look into the illness MCAS which is often a very good example of sudden onset allergies