scombroid histamine food poisoning due to spoiled fish

introduction

a form of potentially fatal dose related food poisoning due to a build up of chemical toxins due to inadequate refrigeration in certain types of fish such as:
- Scombroidea fish (eg, large dark meat marine tuna, albacore, skipjack, bonito, marlin)
- other fish, such as mahi-mahi, amberjack,sardine, yellowtail, herring, and bluefish
symptoms are related to the ingestion of biogenic amines, especially histamine which may be present at 20-50 mg per 100 g of fish (compared with the usual levels of < 0.1mg per 100g)
histamine is produced via bacterial decarboxylation of histidine
scombroid poisoning is the most common chemical agent type of food-borne disease found in the US
more common in nations with a warm water fishing industry
cooking does not deactivate the toxins
it is difficult to detect at risk spoiled fish although some may taste peppery

degree of symptoms depends upon:
- concentration of toxins
- amount of fish ingested
- how cold the fish was before cooking - thawed surfaces may contain more toxins
- individual sensitivities to histamines
- concurrent medications which may interfere with histamine metabolism such as isoniazid (via blockade of GI tract histaminase)
onset of symptoms is usually 10-30 minutes after ingestion and are similar to those of anaphylaxis
flushing, anxiety, palpitations, headache, oral paraesthesiae
abdo pain, nausea, vomiting
diffuse, macular, blanching erythema
tachycardia
wheezing
hypotension or hypertension

diagnosis is clinical although a normal serum tryptase within 1-2 hours potentially excludes anaphylaxis as a cause
histamine levels in the fish can be measured to confirm diagnosis is needed