The short version
- Scombroid poisoning is histamine poisoning from fish that was not kept cold after it was caught; cooking and freezing do not remove the histamine[2].
- CDC counted 192 US scombroid outbreaks and 597 illnesses from 2011 to 2023, and 76% of outbreaks with a known food were tuna[1].
- Symptoms usually start 10 to 30 minutes after eating: flushing, rash, a peppery taste, diarrhea and cramps[4][2].
- It responds well to antihistamines, but a severe case can look exactly like anaphylaxis and should be treated as anaphylaxis first[3][5].
What is scombroid poisoning?
As the North Carolina Division of Public Health explains, bacteria in warm fish turn the natural histidine in the flesh into histamine[2]. Hungerford’s review calls it unique among seafood toxins because it comes from mishandling, not from the food chain[3].
| Scombroid | Ciguatera |
|---|---|
| Caused by warm storage after the catch[3] | Toxin made by algae and carried up the food chain[1] |
| Tuna, mackerel, mahi mahi, amberjack, bluefish, sardines[2] | Barracuda, grouper, amberjack and other reef predators[1] |
| 192 outbreaks, 6 hospitalizations, 2011 to 2023[1] | 189 outbreaks, 67 hospitalizations, 2011 to 2023[1] |
| Prevented by chilling fast[2] | Resistant to cooking or freezing[1] |
The full ciguatera picture is in ciguatera poisoning.
The US outbreak data
The numbers come from CDC’s 2026 surveillance summary of marine toxin outbreaks[1].
| Measure, 2011 to 2023[1] | Scombroid |
|---|---|
| Outbreaks | 192 (48% of all marine toxin outbreaks) |
| Illnesses | 597 |
| Hospitalizations | 6 |
| Fish implicated | Tuna in 76% of outbreaks with a known food |
| Top reporting states | New York 43, Florida 38, California 23, Hawaii 18 |
| Imported fish | 53% of outbreaks with a known import status |
CDC’s prevention message is one line: keep seafood below 40 °F (4.4 °C) from catch to consumption[1]. Holding fish at or above that temperature lets bacteria make histamine[1].
Symptoms and how it differs from an allergy
| Feature | What to expect |
|---|---|
| Onset | Usually 10 to 30 minutes after eating[4] |
| Common signs | Facial flushing, sweating, rash, burning or peppery taste, diarrhea, cramps[2] |
| Severe signs | Breathing difficulty, tongue and throat swelling, blurred vision[2] |
| Course | Usually settles within several hours[2] |
| Who gets it | Anyone who eats the fish; no prior allergy is needed[5] |
A clue at sea: several crew who ate the same tuna flush at once, which points to the fish rather than an allergy in one person.
Treatment on board
- Mild flushing and rash: an H1 antihistamine; in one case the patient improved and went home on it[4][3].
- Wheeze, swelling or low blood pressure: treat as anaphylaxis with adrenaline. An intensive care nurse needed two doses plus an infusion after canned tuna[5].
- Get radio medical advice for any breathing problem, and start the medevac decision if the person does not improve.
- Bag and freeze the leftover fish so the batch can be tested, and pull the rest of it from the galley.
- Log every case with meal time and onset in the medical log.
Do not trust smell or cooking
Histamine is not destroyed by freezing or cooking, so chilling fish promptly after the catch is the most effective prevention[2].
A cold-chain plan for vessels that catch or serve fish
| Step | Why |
|---|---|
| Chill immediately after the catch | Rapid chilling is the most effective prevention[2] |
| Hold below 40 °F (4.4 °C) all the way to the plate | CDC’s prevention target[1] |
| Log fish-hold and galley fridge temperatures | Improper temperature control can occur at any point, including transport[1] |
| Reject warm deliveries | Over half of outbreaks with known import status involved imported fish[1] |
Discovery Health MD covers the medical side of crew food safety: ship medical chest management for antihistamines and adrenaline in the chest, and maritime medical consulting for galley and outbreak protocols. See also norovirus on ships and illness reporting for US ports. Have a physician review your galley plan.
Common questions
What causes scombroid poisoning?
Histamine made by bacteria in fish that was held too warm after it was caught[2][1].
Which fish cause scombroid poisoning?
Mostly tuna and mackerel, but mahi mahi, amberjack, bluefish and sardines have also been implicated[2]. Tuna caused 76% of US outbreaks with a known food[1].
How fast do symptoms start?
Usually within 10 to 30 minutes of eating[4].
How long does scombroid poisoning last?
Symptoms usually disappear within several hours[2].
Does cooking kill scombroid toxin?
No. Histamine is not destroyed by freezing or cooking[2].
Is scombroid an allergy?
No. It is histamine toxicity, so anyone who eats the fish can react without prior sensitisation[5].
How is it treated?
Antihistamines for mild cases; severe cases are treated as anaphylaxis until proven otherwise[3][5].
