Scromboid (histamine fish poisoning) can be easily misdiagnosed since its' clinical presentation can mimic that of allergy. Seen most frequently in the summer and occurring with Scombroideafish (tuna, mackerel, bonito, skipjack) but also with large dark meat fish (sardines and anchovies) and even more commonly with nonscromboid fish such as mahi mahi and amber jack. In warm conditions when fish is improperly refrigerated, bacterial histidine decarboxylase converts muscle histidine into histamine which quickly accumulates. Histamine is heat stable and not destroyed with cooking. 

• Clinical features: Intense flushing of face, neck, and upper torso, urticaria, abdominal cramps, headache, palpitations, diarrhea, nausea, vomiting, burning of the mouth and throat.
• Symptoms begin within minutes of ingestion and typically last several hours
• Self limiting condition. Mainstay of treatment is H1 blockers (antihistamines) and good supportive care. If bronchospam present steroids and inhaled B2 agonists should be administered.

Bottom Line:

Scromboid poisoning is due to histamine ingestion and is often misdiagnosed as allergic reaction. It is preventable with proper fish storage.

References

Severe scombroid fish poisoning: an underrecognized dermatologic emergency.  Jantschitsch C, Kinaciyan T, et al. J Am Acad Dermatol 2011; 65:246–7.

Histamine fish poisoning: a common but frequently misdiagnosed condition. Attaran RR, Probst F. Emerg Med J 2002;19:474–5.