What Is a Food Allergy?
When a person has a food allergy, the body reacts as though that particular food product is harmful. As a result, the body’s immune system (which fights infection and disease) creates antibodies to fight the food that triggers the allergy. The next time a person comes in contact with that food by touching or eating it or inhaling its particles, the body releases chemicals, including one called histamine, to protect itself. These chemicals trigger allergic symptoms that can affect the respiratory system, gastrointestinal tract, skin, or cardiovascular system.
What Causes Food Allergies?
Doctors cannot predict which children will have food allergies and which children won’t, but some factors may place a child at higher risk for developing food allergies. “The capacity to be an allergic person is inherited,” says Michael Young, MD, a pediatric allergist and immunologist and author of ‘The Peanut Allergy Answer Book’.
There is nothing parents can do that will completely eliminate the possibility that their child will develop food allergies. However, breast-feeding (especially exclusive breast-feeding that is not supplemented with infant formula) can help infants who are especially prone to milk or soy allergies avoid allergic reactions. When an infant consumes only breast milk, she has a decreased exposure to foods that can cause allergies. Some doctors also recommend that allergy-prone babies not be fed solid foods until six months of age or later to avoid exposure to allergenic foods.
Some Common Food Allergens
A child could be allergic to any food, but there are eight common allergens that account for 90% of all reactions in children. The most common food allergens in children include:
Milk, eggs, peanuts, tree nuts (such as walnuts and cashews nuts), fish, shellfish (such as shrimp), soy, wheat.
“In general, most common food allergies, such as milk, egg, wheat, and soy allergies, are outgrown in childhood. By age 5, 80% to 85% of children have outgrown milk or egg allergy,” Dr. Young says.
A common skin symptom of a food allergy is hives, or raised red itchy bumps on the skin. Swelling of the face, throat, lips, and tongue may also occur, often within minutes of contact with the food. Respiratory symptoms such as wheezing and trouble breathing or gastrointestinal symptoms such as sudden abdominal pain and vomiting are also common reactions.
When a child has a serious allergic reaction with widespread effects on the body, this condition is known as ‘anaphylaxis’. A child with anaphylaxis, which can involve the heart, lungs, blood vessels, and other body systems may feel dizzy or lightheaded or even lose consciousness. Other indications that the food allergy reaction is serious include a rapid heart rate, difficulty breathing because of a swelling in the throat and airways, or a life-threatening drop in the blood pressure (which is also known as anaphylactic shock). Without rapid emergency medical treatment, children with anaphylaxis can die if they are unable to breathe or collapse due to shock.