Stomach pain after eating fish is not normal, and you should see a doctor for evaluation. It is possible that your pain is from a problem such as spoiled fish, but if you regularly have pain, you probably are allergic to fish. More than 7 million Americans suffer from a fish allergy, according to the Food Allergy and Anaphylaxis Network. Fish allergies can cause a life-threatening reaction. See your doctor for a diagnosis.
Cause
If the pain in your stomach after eating fish is from an allergic reaction, it is the result of inflammation and swelling in the intestines. Your immune system fails to recognize the proteins found in the fish as safe and begins to develop defenses to fight off the proteins, according to the Mayo Clinic website. Histamine is released by cells throughout the body, specifically in soft tissue such as the digestive tract, and it causes soft tissue to become inflamed, leading to common fish allergy symptoms.
Effect
Inflammation in the gut can lead to nausea, vomiting, diarrhea, abdominal pain, cramping, gas and bloating. You also might develop other symptoms, including nasal congestion, sneezing, watery eyes, shortness of breath, chest tightness, wheezing, coughing, eczema, skin rashes or hives. A severe allergic reaction will cause facial swelling, dizziness and difficulty breathing.
Testing
If you experience stomach pain after eating fish consistently, your doctor might recommend allergy testing. Allergy tests use your blood and skin pricking to determine if your body produces IgE antibodies after exposure to fish protein. You also can participate in an elimination diet where you remove fish from your diet for two weeks and then slowly re-introduce it back into your diet to see if you develop allergy symptoms.
Avoidance
There is no cure for a fish allergy, but the condition is manageable. The federal government requires that all packaged foods clearly disclose the use of fish on the products label. Read all ingredients, and avoid consuming any form of fish. When eating out, ask your server if any of the dishes contain fish products.
Treatment
If you accidentally ingest fish, call your doctor. You can treat minor allergic reactions with an over-the-counter antihistamine. Antihistamines restrict the body from producing histamine, alleviating common allergy symptoms. You also can use steroid-based creams such as hydrocortisone to treat skin reactions.
