HISTAMINE FISH POISONING Histamine fish poisoning is among the most common toxicities related to fish ingestion. It is due to 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. Toxin production occurs when inadequate refrigeration allows the multiplication of bacteria that contain histidine decarboxylase, which converts amino acid histidine in the fish tissues to histamine. Subsequent cooking, smoking, or canning of the fish does not eliminate the histamine. Affected fish do not have a distinctive appearance or odor. Occasionally, fish with higher histamine concentrations may have a pungent, peppery taste or bitter taste. Typical manifestations of histamine fish poisoning include skin flushing on the upper half of the body, rash, gastrointestinal (GI) complaints, and throbbing headache. The manifestations in details include Erythema of the face, neck, and upper torso Headache (severe and throbbing) Dysphagia Nausea and vomiting Abdominal cramps or epigastric pain Diarrhea Palpitations Pruritus Dizziness Dry mouth Angioedema Sense of anxiety or unease Respiratory distress and chest tightness (rare) Loss of vision (rare). Antihistamines such as Loratidine usually relieve the symptoms and support histamine as the causative agent. In severe cases, patients may require treatment for bronchospasm or hypotension (a decrease in blood pressure below normal).