allergenic cross-reactivity

Allergenic cross-reactivity occurs when your immune system mistakes proteins in one food or substance for similar proteins found in another, triggering an allergic reaction. This happens because certain proteins share similar structures, causing your body’s immune defenses to react as if they’re the same allergen. For example, someone allergic to birch pollen may also react to apples because their proteins resemble each other. Cross-reactivity explains why some people experience allergic symptoms across different foods or plants that share similar allergenic proteins.