Most people with food allergies have them as a baby or child – and many grow out of them as their body realizes the allergen isn’t harmful to them.
But some adults have reported allergies developing later in life, although the reasons behind this aren’t conclusive. It could be that they’ve always been allergic to something but never been exposed to it before, or in high quantities. Being immunocompromised due to illness or pregnancy can also cause people to develop allergies as an adult.