cross-reaction

This case of mistaken identity, at the molecular level, is known scientifically as a cross-reaction.

Eating those foods can trigger a “cross-reaction,” making allergy symptoms worse, but more often they cause oral-allergy syndrome, also known as pollen-food syndrome: itchy mouth, scratchy throat, swelling of the lips, mouth and throat.

A drug your doctor prescribes could be perfectly safe and effective, but if you are taking a similar-acting supplement, there is a real danger of cross-reaction.