Histamine fish poisoning (previously known as scombrotoxic fish poisoning, scombroid, pseudo allergic fish poisoning, mahi mahi flush)/ histamine poisoning
Scombrotoxin poisoning occurs between a few minutes to a few hours of eating scombroid fish, for example mackerel or tuna. Other types of fish may be involved. It is caused by histamine produced from tryptophan by marine microbes contaminating fish flesh.
Features include hot flushing with headache and diarrhoea. Recovery occurs after a few hours.
Aetiology:
- histamine
- inadequate refrigeration allows multiplication of bacteria that contain the enzyme histidine decarboxylase (HDC). HDC converts histidine in fish tissues to histamine. Subsequent cooking / smoking does not diminish the levels of histamine
- histamine can also be present as a consequence of fermentation in the production of foods such as certain cheeses or sausages
Reservoir:
- inadequately preserved and improperly refrigerated fish. Approximately 100 different species have been implicated:
- scombroid dark-meat fish e.g. tuna, mackerel, skipjack, bonito, marlin (most commonly);
- non-scombroid species e.g. mahi-mahi (dolphin fish), amber jack, sardine, yellowtail, herring, and bluefish;
- whitefish (very rarely)
- has also been associated with the consumption of cheese and other fermented foods
Epidemiology:
- accounts for approximately 5% of food-borne disease outbreaks reported to US Centers for Disease Control and Prevention (CDC)
- during 1998-2008, 262 confirmed and 71 suspected outbreaks were reported to CDC
- seasonal variation is observed with more cases occurring during summer months
- between 2001 and 2007, there were 2 reported incidents to the UK Food Standards Agency linked to histamine in cheese; between 2008 and 2015, there were twenty such reported incidents
Transmission:
- Person-to-person spread does not occur
Common clinical features:
- features occur 2 minutes to 2 hours after ingestion
- flushing, sweating, rash, diarrhoea, vomiting, abdominal pain and headache. Occasionally, a metallic taste or burning/swelling of the mouth
- symptoms usually resolve within a few hours
- cases with a history of atopy or those taking certain medications (e.g. isoniazid or doxycycline which slow histamine metabolism by the liver) may have more severe symptoms and/or prolonged illness
- rare complications include bronchospasm, angioedema, hypotension, pulmonary oedema, and cardiogenic shock
- long term health consequences have not been reported
Infectivity:
- person-to-person spread does not occur
- suspected fish/foods should be discarded to prevent further cases as cooking, canning, smoking or other processing does not diminish the levels of histamine
Reference:
- PHE (2019). Recommendations for the Public Health Management of Gastrointestinal Infections 2019 Principles and practice A joint guidance from Public Health England and the Chartered Institute of Environmental Health