Anaphylaxis versus Anaphylactoid Reactions
Anaphylaxis refers to a systemic, immediate hypersensitivity reaction due to the IgE-mediated release of mediators from mast cells and basophils.
Anaphylactoid reactions refer to clinically similar events as anaphylaxis but are not mediated by IgE. They cause, via an unknown mechanism, the degranulation of mast cells and/or basophils.