Abdominal pain with fullness, pressure and a rash after eating is most likely the result of a food allergy. Although you can be allergic to any food, 90 percent of food allergies are caused by these seven foods, according to the Mayo Clinic: fish, shellfish, nuts, soy, wheat, eggs and dairy. Food allergies are commonly discovered during childhood when the food is first introduced, but it is possible to develop a food allergy later in life. These symptoms need to be evaluated by a medical doctor because an allergic reaction to a food can lead to serious complications.
Cause
Your immune system defends the body against dangerous substances such as viruses, toxins and bacteria, according to Medline Plus. If you're allergic to a specific food, your immune system experiences an exaggerated immune reaction to the proteins found in the food. This causes your body to create an allergy-producing substance, immunoglobulin E, or IgE antibodies, to fight off the proteins. Part of this reaction is the creation of histamine, a chemical that causes inflammation to form in soft tissue. Histamine is the main chemical that can cause abdominal pain and skin rashes.
Symptoms
The abdominal pain with fullness and pressure is the result of excessive gas and bloating in the digestive system. Histamine in the soft tissue of the intestines causes inflammation and swelling to occur. This can lead to stomach cramping, gas, abdominal pain, nausea, vomiting and diarrhea, according to the University of Maryland Medical Center. Skin rashes are common with a food allergy, especially hives and eczema. These skin rashes typically form within a few minutes of eating the food and are very itchy and can spread when scratched.
Testing
In order to effectively treat your symptoms, your doctor may want to run some allergy tests on you. Common food allergy proteins are taken and injected directly under the top layer of skin. Within 15 minutes of the injection you will develop inflammation and swelling to the certain proteins that you're allergic to. Blood tests may also be performed by introducing the same proteins to a sample of your blood. If your blood produces IgE antibodies, you're allergic to that food, according to the Mayo Clinic.
Treatment
Abdominal pain, gas, bloating and skin rashes from a food allergy are most effectively treated by avoiding the foods that you're allergic to. Avoiding certain foods may be more difficulty than it first appears. For example, milk proteins may be found in hard candies, non-dairy creamers and chocolate. Wheat proteins may be used in ice cream, ketchup and salad dressings. Read all product labels to avoid an allergic reaction.
