What are Food Allergies?

Allergic reactions to foods are caused by the immune system overreacting to a specific component of the provoking food. When these reactions occur in infants and young children it can be especially frightening for the child and the family. Food intolerance and other cause of adverse reactions are often misdiagnosed as food allergies. Characteristics of allergic reactions to foods may include:

Symptoms begin within minutes to hours of food exposure by ingestion, inhalation, or contact.

Reactions range in severity from mild to life threatening.

Symptoms vary from person to person but commonly involve the gastrointestinal tract (abdominal pain, vomiting, diarrhea, difficulty swallowing), skin (hives, swelling), lungs (coughing, wheezing, difficulty breathing), or cardiovascular system (fainting, shock).

How do you test for food allergies?

Food allergy testing consists of testing for the presence of specific IgE antibodies to foods or histamine release in the skin in response to a food. RAST or the radioimmunosorbent assay test looks for  presence of elevated
food specific IgE antibodies in the blood. Skin testing for food allergy consists of applying extract to pricked skin or injecting small amounts of the extract under the skin. Histamine is used as a control. The test is considered
positive if a hive occurs as large as or larger than the histamine control. The larger the reaction the more likely a significant food allergy exists. Questionable reactions on skin prick or scratch test are usually followed by an intra-dermal skin test. In contrast to pollen allergy, food allergy skin testing may be less reliable.

What are the most common foods that cause allergic reactions?

The most common food allergens are peanut, cow’s milk, wheat, corn, soy, shellfish, eggs, and tree nuts.

How are food allergies treated?

Food allergy is treated by avoidance of known food allergens. Those foods are then simply avoided.
Desensitization to foods is not very effective like it is for pollen allergy.

(information obtained from National Jewish Pediatric Allergy Program and Dr. Scot Lewey (www.thefooddoc.com)