IGHE and urticaria: Clinical and murine‐based evidence indicate that the symptoms of food allergy are driven by allergen/IgE/FcεRI‐mediated mast cell degranulation and release of mast cell mediators that act on target cells to promote the pathophysiologic features of disease, including urticaria, diarrhea, bronchoconstriction, respiratory and cardiovascular collapse, the latter of which reflects a decrease in intravascular volume resulting in decreased vital organ perfusion and shock 10, 11, 14, 15, 40, 41, 42, 43.