Approximately 60% of perioperative
anaphylactic reactions are thought to be
immunoglobulin IgE mediated, whereas 40% are thought to be non-
IgE mediated hypersensitivity reactions (both considered non-dose-related type B
adverse drug reactions). In both cases, symptoms are elicited by mast cell degranulation. Also, pharmacological reactions to drugs (type A, dose-related) may sometimes mimic symptoms triggered by mast cell degranulation. In case of
hypotension,
bronchospasm, or urticarial
rash due to mast cell degranulation, identification of the responsible mechanism is complicated. However, determination of the type of the underlying
adverse drug reaction is of paramount interest for the decision of whether the culprit
drug may be re-administered.
Neuromuscular blocking agents (NMBA) are among the most frequent cause of perioperative
anaphylaxis. Recently, it has been shown that NMBA may activate mast cells independently from
IgE antibodies via the human Mas-related
G-protein-coupled receptor member X2 (MRGPRX2). In light of this new insight into the patho-mechanism of pseudo-allergic
adverse drug reactions, in which as
drug-receptor interaction results in
anaphylaxis like symptoms, we critically reviewed the literature on NMBA-induced perioperative
anaphylaxis. We challenge the dogma that NMBA mainly cause
IgE-mediated
anaphylaxis via an
IgE-mediated mechanism, which is based on studies that consider positive skin test to be specific for
IgE-mediated hypersensitivity. Finally, we discuss the question whether MRGPRX2 mediated pseudo-
allergic reactions should be re-classified as type A adverse reactions.