Perioperative Allergic Reactions to Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

Introduction to Allergic Reactions

The patient likely presents with cross-reactive hypersensitivity to multiple NSAIDs, manifesting as non-specific histamine release reactions or anaphylaxis of Grade I-II, and should avoid all NSAIDs and be urgently referred for specialized allergologic study before any future surgical procedure, according to the British Journal of Anaesthesia 1, 2

The patient's reaction pattern is highly suggestive of NSAID hypersensitivity, with consistent clinical presentation of facial flushing and body pruritus on both occasions, corresponding to a Grade I reaction according to the modified Ring and Messmer scale, as noted by the British Journal of Anaesthesia 2, 3
The characteristic timing of reactions, occurring in the postoperative nocturnal period, is compatible with reactions that can present up to one hour after administration, especially with intravenous infusions, as reported by Anaesthesia 1, 2

Reactions to paracetamol and other NSAIDs can occur through several mechanisms, including non-specific histamine release, as suggested by the British Journal of Anaesthesia 3
The patient's reaction to two different medications (paracetamol in 2019 and enanthium in 2025) strongly suggests cross-reactive hypersensitivity among NSAIDs, according to Anaesthesia 4, 1

The patient requires specialized allergologic evaluation, including serum tryptase, skin prick tests for paracetamol, enanthium, and a complete panel of NSAIDs, and specific IgE serum tests, as recommended by the British Journal of Anaesthesia 2, 8, 9

For future elective surgeries, the patient should not undergo surgery until allergologic study is completed, and should avoid paracetamol, enanthium, and all NSAIDs, as advised by the British Journal of Anaesthesia 8, 9
In case of emergency surgery, alternatives such as opioids, regional/neuroaxial anesthesia, and local anesthetics like lidocaine or bupivacaína should be considered, as suggested by the Journal of Allergy and Clinical Immunology and Anaesthesia 5, 4

It is crucial not to assume paracetamol is "safe" or "non-allergenic", as it can cause severe cutaneous reactions and histamine release, as noted by Anaesthesia and the British Journal of Anaesthesia 1, 2, 8
The patient's history should be carefully documented, including a detailed narrative of both events, timing of medication administration, and response to treatment, as recommended by the British Journal of Anaesthesia 9