If you develop diarrhea after eating oysters, you may have an allergy to shellfish or you may be experiencing food poisoning. A shellfish allergy is one of the most common food allergies among children and adults, according to MayoClinic.com. If you are allergic to oysters, you will develop other symptoms alongside diarrhea and other gastric symptoms. Food poisoning is another consideration because oysters can contain certain parasites, bacteria or oysters, if they are not properly cooked. Talk with your doctor if you develop diarrhea that has lasted for more than two days.
Shellfish Allergy
Every food is created with certain proteins that the body breaks down during digestion. If you are allergic to oysters and other shellfish, your immune system doesn't recognize the proteins in the seafood as a safe substance. Instead, the immune system reacts to the proteins as if they were harmful. A defense is built with antibodies and other chemicals in the body. The release of these chemicals in the lining of the intestines causes inflammation and swelling, leading to diarrhea and other digestive complications.
Symptoms
Diarrhea is a common symptom of an allergic reaction to oysters, but it will be accompanied by other common food-related allergy symptoms. You may develop stomach cramping, vomiting, bloating, abdominal pain and nausea. Other common symptoms of a food allergy include asthma, shortness of breath, wheezing, coughing, eczema, hives, skin rashes, tingling in the mouth, nasal congestion and sinus pain.
Food Poisoning
MedlinePlus states that oysters are a common food that is related to food poisoning. If you have consumed oysters before and didn't develop diarrhea, food poisoning is a likely diagnosis. This condition occurs when you eat oysters that are contaminated with a virus, bacteria or parasite. Within two to four hours, you will develop stomach pain, cramping, vomiting and diarrhea. Call your doctor at the first sign of food poisoning for a proper diagnosis.
Considerations
Dehydration is a concern when you have diarrhea. Diarrhea caused by both of these conditions should subside after the oysters have been eliminated from the body. If the diarrhea continues, you may have another medical condition.
Anaphylaxis, or a severe allergic reaction, may occur if you are allergic to other shellfish. Anaphylaxis causes your body to go into a state of shock that could be life-threatening. Common symptoms of this condition are swelling in the lips, face or tongue, hives, shortness of breath and dizziness. Call 911 if these symptoms develop.
