Prather Pediatric and Allergy Center - Ask Doctor Brent

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Title: Food Allergies - Facts and Fallacies

Category: Asthma and Allergy


Dr. Bock from the National Jewish Center for Immunology and Respiratory Medicine in Denver, Colorado published an in depth study of food allergies in the Journal of Pediatrics, October 1990. In his study he confirms that the only accurate way to diagnose food allergies is to use a double blind oral challenge. This means a patient is fed food and symptoms are observed. The food ingested is not known by the patient and is disguised in the form of a capsule or caplet. Also placebo is given and any reactions from that are noted. In their study over a fifteen year period of 500 patients, they confirmed a suspicion of food allergies in 185 children or about 40 % of those tested. Ninety-five percent of the reactions were to eggs, peanuts, cows milk, tree nuts, soy and fish. These have always been suspected as the most common foods causing food allergies. Skin testing on the other hand is a very inaccurate way to diagnosis food allergies and is discouraged in the conclusion of this study. Foods injected into the surface of the skin may cause some redness giving one a false impression of allergy. This can lead to an unnecessarily restrictive diet and over treatment. The true gold standard as confirmed from this study for food allergies is double blind oral food challenge testing. A simpler way to do this test is to restrict the suspected food from the diet for a few weeks and then to challenge with the food in your doctor's office and observe for any suspicious allergy symptoms. Full blown anaphylaxis can occur from severe food allergies and should be treated with adrenalin. For children who are at risk for such food allergies, it is recommended by the American Academy of Pediatrics and the American Academy of Allergy that a pre-dose injectable adrenalin kit be available at their school. This could have prevented several deaths which occurred last year from food allergy. Ideally a school nurse or a teacher would be assigned and trained to properly use this in case of such an emergency.

In summary, the true gold standard for diagnosing food allergies is double blind oral challenge testing. Skin testing can occasionally be a guide but is inaccurate and leads to many false positive reactions. The only treatment for food allergy is to avoid that food until the allergy is outgrown which may in rare cases be a lifetime. For highly susceptible individuals, emergency measures should be planned for, such as having adrenalin and Benadryl and an emergency plan in place to prevent anaphylaxis and even death.