Allergies that affect the stomach and digestion are usually due to food allergens in children and can cause several symptoms, including decreased appetite and diarrhea. According to the Children's Hospital of Wisconsin, approximately two to four percent of children suffer from clinical allergic reactions to food. Although most children "grow" out of their condition, allergies to peanuts, tree nuts and shellfish may endure for life.
Definition
Allergies that affect the gastrointestinal tract occur when allergens affect the stomach and intestines. These allergies can also lead to other body symptoms, as the immune system is triggered to overreact to a food allergen. Other organs of digestion that may also be affected include the liver, gallbladder and pancreas.
Symptoms
Cow's milk is the most common food allergen that causes abdominal symptoms in children and infants. Common symptoms include colic, vomiting, abdominal pain, constipation, diarrhea, bloating or swelling of the stomach area and decreased appetite. MayoClinic.com lists other common food allergens in children, including peanuts, tree nuts and eggs.
Effects
Food allergies occur because proteins called antibodies are released in response to specific foods that are eaten or even touched, in severe cases. Antibodies are normally released by the immune system in response to germs or pathogens in the body. In an allergic reaction, the immune system becomes over-sensitized and recognizes harmless food molecules as dangerous to the body, triggering an inflammatory response. The allergic reaction can cause bloating, pain, diarrhea and vomiting. Anaphylaxis, a condition in which the mouth, throat and respiratory tissues swell, making it difficult to breathe, and the blood pressure drops, can be life-threatening. In children, this typically occurs due to an allergy to peanuts or shellfish.
Difference
Food intolerance is not the same as food allergies, though both can cause similar gastrointestinal symptoms. Food intolerance disorders include lactose intolerance, celiac disease and cystic fibrosis. Lactose intolerance occurs due to a deficiency of the enzyme lactase in the small intestinal mucosa; it is not the same as milk allergy. Celiac disease is an intolerance to foods containing wheat, barley and rye. Individuals with cystic fibrosis also suffer from food intolerance related to a pancreatic enzyme deficiency that causes a high concentration of sodium and chloride in the sweat and pulmonary or respiratory system.
Babies
In infants, food allergy symptoms include colic, which causes stomach swelling, gassiness, vomiting and diarrhea, leading to crying and lack of appetite due to the discomfort. The Children's Hospital of Wisconsin reports that colic can be related to allergic reactions because the baby's undeveloped immune system becomes hypersensitive to certain foods. These include allergic reactions to milk and soy in infants and young children.
Skin
Symptoms of food allergies in children and babies may also affect other areas in addition to the gastrointestinal tract. The Food Reactions website notes that up to 50 percent of children will experience skin rashes such as hives and eczema due to food allergens. These skin reactions may occur immediately or shortly after the specific food is eaten. The Children's Hospital of Wisconsin warns that in some cases a skin rash can indicate a food allergy even if other symptoms do not occur.
