Marine Poisoning (Ciguatera & Scombroid)

Distinct from envenomation — this is an accumulated toxic compound in fish that poisons the person who eats it, rather than a sting or bite.

Ciguatera

From reef fish, usually from Pacific Island regions.

• GI symptoms start several hours after eating; diarrhoea persists about 5 days on average.
• ~24 hours later, neurological effects develop — typically distal paraesthesia and cold allodynia (burning pain on exposure to cold), the classic diagnostic clue.
• Resolves over several months.
• No specific treatment — discuss with an expert/toxicologist.

Scombroid

Caused by ingesting improperly stored/cooked fish (tuna, mackerel, kingfish, and others) that has developed high histamine concentrations from spoilage.

• Presents like an allergic reaction: urticaria, erythema, pruritus, flushing; nausea/vomiting, abdominal cramps, diarrhoea; headache. Severe cases can have wheeze, dyspnoea and hypotension.
• Onset within 2 hours after eating; resolves in 12–48 hours untreated (even severe cases improve within hours of antihistamine treatment).

Treatment:

• Antihistamines
• Bronchodilators if wheeze
• IV normal saline for hypotension