Food Allergies

By Peter Galvin, MD
Food allergies are unpleasant and sometimes dangerous immune reactions to certain foods. People with food allergies may develop hives, itching, flushed skin, lip or tongue swelling, throat tightening, shortness of breath, crampy abdominal pain, vomiting, and/or diarrhea soon after eating certain foods. The most severe allergic reaction is anaphylaxis, which can cause wheezing, low blood pressure, palpitations, dizziness or fainting, and death if not treated quickly. In the U.S., nine foods account for over 90% of food allergies – shellfish, dairy, peanut, tree nuts, fin fish, egg, wheat, soy, and sesame. Peanut is the leading cause of death from anaphylaxis in the U.S., followed by tree nuts and shellfish. Some people develop an allergy to red meat, known as alpha-gal syndrome, following a tick bite.
In the U.S., about 8% of children and 11% of adults have food allergies. The strongest risk factor for developing food allergies is having eczema as an infant. Food allergies also run in families and may be associated with overuse of antibiotics or living in urban areas or industrialized countries. A food allergy can be diagnosed with a blood test or skin prick test done by an allergist to detect food-specific immunoglobulin E (IgE) antibodies. An allergist may also perform an oral challenge test, in which an individual eats a specific food of concern, and a subsequent allergic reaction confirms a food allergy diagnosis. This may trigger a severe reaction, so it must be done under close medical supervision.
Those with mild food allergies can take an oral antihistamine, for example cetirizine or diphenhydramine, to relieve itching, mild abdominal upset, or small areas of hives or swelling. More severe reactions require intramuscular injections of epinephrine (EpiPen), which may need to be repeated every five minutes if symptoms persist. Anyone experiencing food-related anaphylaxis should seek immediate emergency medical care, where they will receive additional epinephrine, antihistamines, steroids, or inhalers. Some people with food allergies may undergo oral immunotherapy, also called food allergy desensitization. Administered by an allergist, this involves consumption of small, successively increasing amounts of a food allergen, and then maintenance of a daily target amount indefinitely. Currently, only oral immunotherapy for peanut allergy has received U.S. Food and Drug Administration approval. This therapy for peanut allergy often begins in early childhood.
Obviously, those with food allergies need to avoid the food that triggers their allergic reaction, which requires careful reading of packaged food labels. These labels are required by U.S. federal law to list any of the nine most common foods that cause allergic reactions. Those with food allergies should also disclose their food allergies when eating at restaurants, schools, and other venues. Those with food allergies should know how to identify and treat mild, moderate, and severe allergic reactions. Those with more severe reactions should always carry epinephrine injectors with them, while those with more moderate reactions should carry an antihistamine or inhaler to treat food allergy reactions.
For more information go to the website of the American College of Allergy, Asthma, and Immunology at www.acaai.org
Please direct questions and comments to editor@rockawaytimes.com