Although not an allergic condition, this illness can be confused with an allergic reaction.  Occurring minutes to hours after eating certain fish which has been allowed to thaw and spoil, “Scombroid Poisoning”  can produce facial flushing, sweating, upper body rashes and itching, mouth sensations, palpitations, abdominal cramps, vomiting and diarrhea. It is usually self-limited...but it can be life-threatening.  (See JAMA, March 14, 2001, Vol 285, No 10).

Also called “histamine poisoning” because the toxin produced is histamine, this condition mainly involves scombroid fish (eg. tuna, mackerel, bonita...).  It can also occur with intake of spoiled salmon, bluefish, anchoves, sardines, herring, mahi-mahi and amberjack.  Once histamine is produced in the thawing process, it is inapparent and it cannot be inactivated by cooking, smoking or frying.  It is more likely to occur in thin slices of fish, as used in tuna burgers and fish salads.

The mainstay of treatment is a liberal dose of an antihistamine (eg. benadryl, 50mg orally or 25mg intramuscularly).  A severe reaction may require emergency treatment appropriate for an anaphylactic episode.

Avoidance requires prompt and constant refrigeration to 0 degrees C.  from the catch to the serving.  A problem is that FDA regulations are restricted to importation  and to interstate commerce.  Local seafood businesses are subject to State inspection and may be more problematic.

In summary, the occurrence of an allergic - like reaction  shortly after eating seafood may be “seafood allergy” or “histamine-scombroid poisoning.  In any case, it is uncomfortable, may be serious, and requires prompt and effective treatment.  An antihistamine is a good start.

GS