Scombroid Poisoning: Causes, Symptoms, Treatment, Prevention

Scombroid poisoning is a form of poisoning that occurs from eating a species of fish containing a high amount of histidine.

Histidine is an amino acid that occurs in fish and when the fish is not kept in a refrigerator, histidine breaks and turns into histamine.

Histamine causes toxicity which is known as scombroid poisoning.⁽¹⁾ Consuming fish with a high quantity of histamine leads to allergic reactions such as hives.

Scombroid poisoning is not a long-term or severe condition. Its mild cases disappear on their own without any medication. Antihistamines may be helpful for a few people. If a person experiences severe chest pain or difficulty in breathing, a local emergency service should be called for.

Eating spoiled fish of certain varieties can lead to scombroid poisoning. The fish species involved are:

• Herring
• Sardine
• Amberjack
• Marlin
• Anchovies
• Tuna
• Mackerel
• Bluefish

All the above fishes contain a high level of chemical histidine. Not storing such fishes properly results in the overgrowth of bacterial strains that are responsible for producing enzymes that turn histidine into histamine. Eating fish containing a high level of histamines leads to symptoms of allergic reaction. Due to this scombroid poisoning is also known as histamine poisoning.

Scombroid poisoning is more likely to occur in people with a low level of enzyme diamine oxidase. This enzyme breaks down histamine from food. Therefore, people with a low level of this enzyme may not be able to break down histamine as well as those with high levels.

The symptoms of scombroid poisoning start a few minutes after eating fish.⁽²⁾ The initial symptoms include those of an allergic reaction, which include:

• Nausea
• Dizziness
• Headache
• Facial flushing
• Sweating
• Peppery taste in the mouth

These initial symptoms may progress to facial rashes, swelling, and hives along with short-term abdominal pain and diarrhea.

The symptoms may last from 4-6 hours to 1-2 days.

Treatment depends on the severity of scombroid poisoning. In mild cases, the symptoms may disappear without medication. Antihistamines may also be helpful to people with this condition.

If the case is severe, immediate emergency help may be needed and the treatment may involve the administration of intravenous fluids, oxygen, and other medications.
The signs of a severe case of Scombroid Poisoning include:

• Chest pain
• Trouble breathing
• Swelling of mouth as well as tongue

If the symptoms are not life-threatening an allergist can be consulted as he can determine if it is an allergic reaction.

Epinephrine injections are not required as scombroid poisoning is not a true allergic reaction.⁽³⁾ Also, antibiotics are of no use as it is not an infection.

If catching your own fish, the best way to keep it fresh is to keep it in a refrigerator. Cooking or freezing the fish may not help in getting rid of histamine.

If eating a fish in a restaurant, there is no way to tell if the fish is spoiled. However, according to CDC, a sharp and peppery taste may indicate spoilage.⁽⁴⁾

Scombroid poisoning can result from eating spoiled fish of certain varieties. The treatment for Scombroid poisoning may depend on the severity.