Perioperative
hypersensitivity reactions are rare, often life-threatening events, and subsequent investigations to identify the culprit are important to avoid re-exposure. All exposures in the perioperative setting may potentially be the cause of a
hypersensitivity reaction, but drugs administered intravenously such as
neuromuscular blocking agents (NMBA), induction agents and
antibiotics have traditionally been reported to be implicated most commonly. It has recently become apparent that there are geographical differences in sensitization patterns related to variation in exposures, referral patterns and performance and interpretation of investigations. Differences in sensitization to NMBAs are partly explained by cross sensitization to
pholcodine, an ingredient in
cough-medicines available in some countries. While NMBAs are the most common causes of perioperative
hypersensitivity in some countries, this may not necessarily be the case in all countries. New and hidden
allergens have emerged as causes of perioperative
hypersensitivity such as blue
dyes,
chlorhexidine and
excipients. Detailed knowledge of the events at the time of reaction is necessary to identify potential culprits including rare and hidden
allergens. Cooperation between allergists and anaesthetists, or other staff present perioperatively, is often needed to identify hidden or even undocumented exposures. The objectives of this review are to provide an overview of the history of investigation of perioperative
hypersensitivity, to describe the differences in causes of perioperative
hypersensitivity emerging over time and to increase awareness about the "hidden
allergens" in the perioperative setting. Some practical advice on how to approach the patient testing negative on all initial investigations is also included.