- Scombroid poisoning occurs after the ingestion of fish with high histamine levels due to improper processing or storage
- One of the most common causes of morbidity associated with fish intake
- First described in scombroid fish of the suborder Scombroidea (e.g., tuna and mackerel) but occurs in other dark-fleshed fish too (e.g., sardines and anchovies)
- fish may be fresh, canned or smoked
- improper refrigeration before processing
- storage of the fish at room temperature after cooking.
- Histamine is heat-stable and remains present after cooking, freezing, canning or smoking.
- Outbreaks are most common in summer.
- Histamine does not change the smell or appearance of the affected fish
- Symptoms begin within 10 to 90 minutes after ingestion
- flushing, rash, urticaria (generally widespread erythema, usually lacking wheals), palpitations, headache, dizziness, sweating, and burning of the mouth and throat.
- Gastrointestinal symptoms can include abdominal cramps, nausea, vomiting and diarrhea.
- Severe complications rarely occur: bronchospasm, respiratory distress and vasodilatory shock
- rash lasts 2–5 hours
- other symptoms usually disappear within 3–36 hours
- Scombroid poisoning is frequently misdiagnosed
- Allergic reactions typically affect one person who has a history of specific allergy
- With scombroid poisoning, more than one person, often with no history of allergies, may be affected.
- Histamine produced by the decarboxylation of histidine in the muscle of the fish is primarily responsible for the condition. The decarboxylation process is induced by enzymes produced by primarily enteric gram-negative bacteria (e.g., Morganella morganii, Escherichia coli, Klebsiella species and Pseudomonas aeruginosa) found in the fish’s cutis and intestines.
- The diagnosis is generally clinical
- can be confirmed by measurement of histamine in spoiled fish
- Diagnosis supported by plasma histamine level or histamine metabolites (e.g., n-methylhistamine) in patient’s urine
Most instances of scombroid poisoning are self-limited
- rapid-acting antihistamines (usually H1-receptor antagonists) often used
- Adrenaline and corticosteroids are generally not indicated
Supportive care and monitoring
- public health authorities should be notified to investigate the source and remove the product from distribution