The most likely cause of the illness characterized by a reversal of hot and cold sensations after eating seafood is ciguatera fish poisoning. This condition is caused by toxins (ciguatoxins) found in certain large reef fish such as snapper, barracuda, grouper, and eel. These toxins are heat-stable, so cooking does not destroy them. A hallmark symptom of ciguatera poisoning is the unusual sensation of hot and cold temperature reversal, where cold stimuli feel hot and vice versa. This symptom often appears within hours to days after eating the contaminated fish, sometimes accompanied by gastrointestinal symptoms like nausea, vomiting, and diarrhea, as well as neurological symptoms such as tingling around the mouth and extremities
. Other types of seafood poisoning, such as scombroid poisoning or shellfish poisoning, do not typically cause the hot-cold sensation reversal. Scombroid poisoning usually causes flushing, hives, and gastrointestinal symptoms, while shellfish poisoning often causes numbness, tingling, or paralysis but not temperature reversal
. Therefore, the distinctive symptom of hot and cold sensation reversal strongly points to ciguatera toxin as the cause of the illness after eating seafood.
