[AndyS]

Scombroid food poisoning is a foodborne illness that results from eating spoiled (decayed) fish.[1] It is the second most common type of seafood poisoning,[citation needed] second only to ciguatera. However it is often missed because it resembles an allergic reaction. It is most commonly reported with mackerel, tuna, bluefish, mahi-mahi, bonito, sardines, anchovies, and related species of fish that were inadequately refrigerated or preserved after being caught. The syndrome derived its name because early descriptions of the illness noted an association with Scombroidea fish (e.g., large dark meat marine tuna, albacore, mackerel); however, the Centers for Disease Control and Prevention (CDC) have identified the largest vector to be nonscombroid fish, such as mahi-mahi and amberjack. Scombroid syndrome can result from inappropriate handling of fish during storage or processing. One of the toxic agents implicated in scombroid poisoning is histamine. Other chemicals have been found in decaying fish flesh, but their association with scombroid fish poisoning has not been clearly established.

Unlike many types of food poisoning, this form is not brought about by ingestion of a bacterium or virus.[1] Histidine exists naturally in many types of fish, and at temperatures above 16°C (60°F) on air contact it is converted to the biogenic amine histamine via the enzyme histidine decarboxylase produced by enteric bacteria including Morganella morganii (this is one reason why fish should be stored at low temperatures). Histamine is not destroyed by normal cooking temperatures, so even properly cooked fish can be affected. Histamine is a mediator of allergic reactions, so the symptoms produced are those one would expect to see in severe allergic responses

Symptoms consist of skin flushing, throbbing headache, oral burning, abdominal cramps, nausea, diarrhea, palpitations, a sense of unease, and, rarely, collapse or loss of vision. Symptoms usually occur within 10–30 minutes of ingesting the fish and generally are self-limited. Physical signs may include a diffuse blanching erythema, tachycardia, wheezing, and hypotension or hypertension. People with asthma are more vulnerable to respiratory problems such as wheezing or bronchospasms. Symptoms of poisoning can show within just minutes, and up to two hours, following consumption of a spoiled dish. Symptoms usually last for approximately four to six hours and rarely exceed one to two days