Fish and Shellfish Poisoning

Reef fish from the tropical and subtropical waters of the West Indies, the Pacific Ocean, and the Indian Ocean pose the greatest threat. Cases have been reported in the U.S. in Hawaii, Guam, Puerto Rico, U.S. Virgin Islands, and Florida. A few isolated cases of ciguatera poisoning have even been noted along the eastern seaboard of the U.S.

More than 400 species of fish, particularly reef fish, are thought to contain the toxin for ciguatera poisoning.

Symptoms of ciguatera poisoning often start from a few minutes to 6 hours after eating the toxic fish. They include many gastrointestinal, neurological, and cardiovascular problems. Each person may have different symptoms. But these are the most common symptoms:

• Nausea

• Vomiting

• Watery diarrhea

• Belly (abdominal) pain

• Headache

• Numbness and tingling feeling around the mouth, arms, and legs

• Tiredness (fatigue)

In more severe cases, you may have muscle pains, dizziness, and sensations of temperature reversal, where hot things seem cold and cold things seem hot. You may also have irregular heart rhythms and low blood pressure. 

These symptoms often go away in a few days. But they may last up to 4 weeks. They can be caused by other health conditions. Always talk with your healthcare provider for a diagnosis.

Treatment for ciguatera poisoning includes easing symptoms and treating any complications. There is no specific antidote for the toxin itself. Generally, recovery takes from a few days to a few weeks. 

Tetrodotoxin is also called pufferfish poisoning or fugu poisoning. It's a much rarer form of fish poisoning. It may be very serious. It's almost exclusively linked to eating pufferfish from waters of the Indo-Pacific regions. There have also been cases of poisonings from pufferfish from the Atlantic Ocean, Gulf of Mexico, and Gulf of California. Some of these include deaths. Pufferfish poisoning is a continuing problem in Japan.

Symptoms often start between 20 minutes and 3 hours after eating the poisonous pufferfish. Each person may have different symptoms. But these are the most common symptoms:

• Numb lips and tongue

• Numb face, arms, or legs

• Feeling of lightness or floating

• Headache

• Nausea and vomiting

• Belly pain

• Diarrhea

• Slurred speech

• Trouble walking

• Extensive muscle weakness

• Convulsions

• Trouble breathing

• Mental impairment

• Irregular heartbeat

Death can happen within 4 to 6 hours of poisoning. Get medical care right away.

Treatment for pufferfish poisoning consists of limiting how much of the toxin the body absorbs. It also includes easing symptoms and treating life-threatening complications. There is no known antidote for tetrodotoxin. 

Scombrotoxin is also called scombroid poisoning or histamine poisoning. It happens after eating fish that have high levels of histamine due to incorrect food handling. It's one of the most common forms of fish poisoning in the U.S. and worldwide. 

Certain fish have high amounts of histidine. As a result of poor refrigeration or preservation, bacteria turn the histidine into histamine. This leads to scombroid poisoning. Contaminated fish may look and taste fresh. But some may taste peppery, spicy, or bubbly. The toxin may form even if the fish has been stored at too high a temperature for only a short time. 

This form of fish poisoning happens worldwide in temperate and tropical waters. It can happen after eating:

• Mahi mahi (dolphin fish)
• Albacore tuna
• Bluefin and yellowfin tuna
• Bluefish
• Mackerel
• Sardines
• Anchovy
• Herring
• Marlin
• Amberjack
• Abalone

Symptoms often start within minutes to an hour after eating affected fish. They typically last 3 hours. But they can last for a few days. Each person may have different symptoms. But the most common symptoms are:

• Tingling or burning feeling in the mouth

• Rash on the face and upper body

• Wheezing or shortness of breath

• Drop in blood pressure

• Throbbing headache

• Hives and itching of skin

• Nausea

• Vomiting

• Diarrhea

• Itching

• Heart palpitations

These symptoms can be caused by other health conditions. Many cases of fish allergy are actually scombroid poisoning. Always talk with your healthcare provider for a diagnosis. 

Treatment for scombroid poisoning is generally not needed. Symptoms often go away without treatment within 12 to 48 hours. This poisoning is rarely life-threatening. Treatment could include antihistamines, such as diphenhydramine and cimetidine.

Specific treatment for all fish and shellfish poisoning is based on:

• Your overall health and medical history

• Extent of the disease

• Your tolerance for certain medicines, procedures, and therapies

• Your opinion or preference