Scombroid food poisoning

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Scombroid food poisoning

Scombroid food poisoning, also called scombrotoxin fish poisoning, is a common seafood illness caused by eating fish that have spoiled and high levels of histamine. It happens when fish isn’t stored properly, allowing bacteria to convert histidine in the fish into histamine. Cooking, smoking, or freezing does not remove histamine, so even well-cooked fish can cause symptoms.

What fish are usually involved
Fish from the Scombridae family are often linked to this, including tuna and mackerel. Other common culprits are mahi-mahi, sardines, anchovies, herring, bluefish, amberjack, and marlin. These fish naturally have higher amounts of histidine.

Symptoms and timing
Symptoms resemble an allergy and usually appear within 10 to 60 minutes after eating. They can last up to two days. Common signs include flushed or red skin, sweating, headaches, itching, blurred vision, abdominal cramps, and diarrhea. Some people may have mouth redness, trouble breathing, or an irregular heartbeat. People with asthma may have more breathing problems.

Diagnosis
Diagnosis is mainly based on the symptoms. A normal blood tryptase level can help distinguish it from a true allergy, and if several people get sick after the same fish, that supports the diagnosis.

Treatment
Most cases improve with antihistamines and fluids. An H2 blocker such as ranitidine can help some people. For severe symptoms, doctors may use epinephrine and sometimes steroids.

Prevention
To prevent scombroid, refrigerate or freeze fish promptly after catch or purchase and keep them cold. Do not rely on cooking to make spoiled fish safe.

Overview
Scombroid poisoning is global and relatively common among seafood illnesses. Deaths are rare.