Scombroid

Background

• Food poisoning from improperly-stored fish
  • Especially common with Scombridae and Scomberesocidae families of fish, which include tuna, mackeral, skip-jack, and bonito, but can also be seen with dolphin fish, tilapia, salmon, swordfish, trout, sardines, and anchovies
• Similar illness can occur from raw milk contamination when making Swiss cheese

Microbiology

• Preformed toxins
• Involves Escherichia coli, Klebsiella species, Vibrio species, Proteus species, Clostridium species, Salmonella species, and Shigella species

Pathophysiology

• Storing fish above 4ºC allows multiple bacteria to grow
  • Can be as short as 2 to 3 hours at 20ºC
• The bacteria produce toxins including histamine
• Histamine is resistant to freezing and cooking
• Ingestion of histamine causes the symptoms, described below

Clinical Manifestations

• Within 1 hour of consumption
  • Feeling flushed and warm
  • Urticaria on face and upper torso
  • Headache
  • Diarrhea
• Can also cause perioral burning, itching, and edema, blurred vision, tachycardia, palpitations, hypotension, and dizziness
• Can occasionally progress to anaphylactoid symptoms with bronchospasm, respiratory distress, and arrhythmias
• Illness is more severe in people taking MOA inhibitors or isoniazid, which prevent breakdown of histamines

Prognosis and Complications

• Symptoms resolve within 12 to 48 hours with no serious sequelae

Management

• Close airway monitoring with intubation and ventilation if required
• Antihistamines, including diphenhydramine, hydroxyzine, ranitidine, cimetidine, which should be continued until 1 or 2 days after resolution of symptoms to prevent recurrence