Histamine fish poisoning results from the consumption of inadequately preserved and improperly refrigerated fish.
It resembles an allergic reaction but is actually caused by bacterially-generated toxins in the fish’s tissues.
Previous terms for histamine fish poisoning were scombroid fish poisoning, pseudoallergic fish poisoning, histamine overdose, or mahi-mahi flush. The term scombroid was used because the first fish species implicated in this poisoning were from the suborder Scombridae, which includes mackerel, tuna, marlin, swordfish, albacore, bonito, skipjack, and almost 100 other species. The term histamine fish poisoning is now considered more appropriate because many cases are from nonscombroid fish. Examples include mahi-mahi (dolphin fish), amberjack, herring, sardine, anchovy, and bluefish.
Symptoms of histamine fish poisoning resemble an acute allergic reaction and usually appear 10–60 minutes after eating contaminated fish. Typical manifestations of histamine fish poisoning include skin flushing on the upper half of the body, rash (see the image below), gastrointestinal (GI) complaints, and throbbing headache.
(See Presentation.) Generally, the diagnosis is made on clinical grounds; no laboratory tests are necessary. If confirmation is required, histamine levels in uneaten portions of the suspect fish can be measured. In addition, elevated histamine levels can be measured in patients’ urine.
An example of a typical histamine toxicity rash, in this case from tuna. Image courtesy of Amanda Oakley, MBChB, FRACP.
See 5 Cases of Food Poisoning: Can You Identify the Pathogen?, a Critical Images slideshow, to help identify various pathogens and symptoms related to foodborne disease.
Without treatment, histamine fish poisoning resolves within 12 to 48 hours with no long-term sequelae. Even severe cases improve rapidly within one to three hours from initiation of antihistamines.
In severe cases, patients may require treatment for bronchospasm or hypotension. (See Treatment and Medication.)