A Case of Suspected Scombroid Poisoning in Intensive Care Staff: Is It Anaphylaxis?

Scombroid poisoning (histamine fish poisoning) is an uncommon foodborne illness that frequently mimics immunoglobulin E-mediated anaphylaxis. We report a case of a previously well 28-year-old intensive care nurse who developed abrupt facial flushing, wheeze, dizziness, and hypotension after consuming canned tuna. Initial observations demonstrated sinus tachycardia and hypotension. She was treated according to established anaphylaxis guidelines with two doses of intramuscular adrenaline, intravenous crystalloid resuscitation, and subsequent adrenaline infusion in intensive care. She recovered rapidly and was discharged the following day. Serial serum mast cell tryptase measurements at approximately one hour, six hours, and 24 hours after symptom onset were all within normal limits. In the absence of previous allergy history and given the temporal association with tuna ingestion, scombroid poisoning was considered as a possible diagnosis. This case highlights the difficulty of distinguishing severe histamine fish poisoning from anaphylaxis in the acute setting and reinforces that life-threatening presentations should initially be managed according to anaphylaxis protocols until an alternative diagnosis can be established.