I Had Facial Flushing, Nausea, And Diarrhea After Eating Tuna. Is This An Allergy To Fish?

This reaction could certainly represent an allergic reaction to tuna. Fish allergy, as noted in Which foods are patients most commonly allergic to, is one of the more common foods to which adults become allergic. Certainly, if you have experienced systemic reactions, including hives, flushing, gastrointestinal symptoms, wheezing, throat swelling, or dizziness after eating some type of fish, you should undergo blood or skin allergy testing to a panel of different types of fish to determine whether you are allergic to these foods. In the event that these tests are negative, there is an alternative explanation for these symptoms.

Occasionally, when tuna, mackerel, mahimahi, or bluefish become contaminated with certain bacteria (usually Proteus or Klebsiella), histamine is formed in the meat of the fish in large quantities. Eating the spoiled fish produces a sharp peppery taste and a burning feeling in the inside of the mouth, followed by nausea, vomiting, facial flushing, and headache. This phenomenon, referred to as “scombroid fish poisoning,” is self-limited and does not cause a person to become allergic following the episode.