Defining A Food Allergy: Part One of the Allergy Series

A food allergy can be described the reaction of the immune system to a harmless food as if it were a threat. While there are several types of immune responses to food, we will focus on one specific type of reaction – where the body produces a specific type of antibody call immunoglobulin E (IgE). The binding of IgE to certain molecules in food triggers the immune system to respond.

The first time a person eats the food, no symptoms may be present. The first time they are exposed to that food, their immune system reacts as if the food is harmful and makes specific IgE antibodies for that allergen. The antibodies then circulate throughout the body and attach to different tissues.

The next time they eat the food an allergic reaction could happen. When ingested, the food allergen binds to the IgE antibodies that have attached throughout the body, releasing massive amounts of chemicals such as histamine. Depending on the tissue where they are released, the chemicals will cause various symptoms, ranging from mild to severe. A severe allergic reaction can include anaphylaxis, a potentially life-threating response.

Anaphylaxis may begin abruptly and could lead to death if not treated immediately. This includes a wide range of symptoms that can present themselves in many combinations. Some symptoms are not as dangerous, but the most severe restrict breathing and circulation.

Affected areas could include:

SKIN: itching, hives, redness, swelling

NOSE: sneezing, stuffy nose, runny nose

MOUTH: itching, swelling of lips and tongue

THROAT: itching, tightness, difficulty swallowing, hoarseness

CHEST: shortness of breath, cough, wheeze, chest pain, tightness

HEART: weak pulse, passing out, shock

GI TRACT: vomiting, diarrhea, cramps

NERVOUS SYSTEM:  dizziness or fainting

Symptoms can begin immediately or several hours after contact. Sometimes the symptoms go away, only to return 2 to 8 hours later. Anaphylaxis is highly unpredictable, but if you begin to experience symptoms you must seek medical attention immediately because it can be deadly.

Common Food Allergies in Infant, Children and Adults

In infants and children:

In adults:

Food allergies usually develop at an early age but can develop anytime. Children can outgrow egg, milk, and soy allergies. However, people who develop allergies as usually adults have them for life.