IGHE and anaphylaxis: It is difficult to distinguish whether this represented a true allergic immunoglobulin E(IgE)-mediated, or anaphylactic, reaction as opposed to a non-IgE-mediated anaphylactoid reaction (also known as non-allergic anaphylaxis by the World Allergy Organization [9]) that can often result from direct activation of complement, mast cells, or basophils by non-immune mechanisms [10].