Scombroid fish poisoning is a toxic reaction caused by the decaying flesh of fish of the scombroid family. Fish of this family include bonito, tuna, sardines, anchovies, mahi,mahi, mackerel, king butterfly fish and kahawai.
All of these fish have dark flesh. Other types of fish may also be responsible for this reaction as well as the above mentioned. Scombroid fish contain a chemical substance called histadine within the meat. If the flesh of the fish reaches temperatures of above fifteen degrees celsius after being caught bacteria that are present in the skin of the fish convert the histadine in to scrombrotoxin. Market stalls are particularly susceptible to this through improper or no cooling facilities The primary component of scombrotoxin is another substance called histamine which causes the toxic reaction known as scombroid fish poisoning.
All forms of cooking have little or no effect in reducing the levels of histamine within an affected piece of fish even if all the bacteria that caused the histamine to be produced have been destroyed. Scombroid fish poisoning varies to other forms of fish poisoning in that the areas of flesh that were most decomposed will contain the highest levels of histamine and therefore only the people who eat from that particular area of flesh will feel ill. Others eating flesh from different areas of the same fish will feel no ill effect whatsoever.
Scombroid fish poisoning is not infectious and it is not an allergic reaction either. The person who was affected by this form of poisoning will have no ill effect from eating this type of fish or fish of the same family on future occasions provided it is caught fresh and stored in proper refrigerated conditions.
Symptoms will start to be felt in thirty minutes to one hour after eating the poisoned fish. Primary symptoms include warm flushes followed by the development of a profuse bright red rash starting on the neck or lower jaw and spreading to the lower abdominal area including the back. The rash is hot and itchy but unlike rashes in allergic reactions there is no swelling of the skin. Other symptoms may include any number or all of the following: a burning feeling in the mouth, a pounding headache, nausea, raised heart beat, dizziness, collapse caused by the lowering of the blood pressure, abdominal pain and diarrhea.
Symptoms may persist for a number of hours after which they will normally subside. In some cases, particularly in children and the elderly symptoms may take longer to disappear.
Prevention of this disorder lies solely in the correct handling of fish. All fish should either be cooked promptly after being caught or refrigerated at a constant temperature at four degrees Celsius until used. Removal of the skin also helps to prevent formation of the toxin by reducing the number of bacteria around the flesh of the fish.
Treatment of this condition is usually quite simple. Oral anti histamine is usually enough to eleviate the symptoms. Expert medical advise should be saught and the patient should receive a full medical exam in an emergency unit to eliminate any complications.