This week a mother and her 5 year-old son visited me for an opinion on his food allergies. She brought with her a 20 page colorful and flashy printout of labs done a few weeks ago. The testing was quite comprehensive in evaluating antibody response to over 100 foods and 30 environmental allergens. It checked for the presence of other antibodies indicating possible celiac disease and also measured total antibody levels of various types. Many foods were identified as positives and most of them were her son’s favorites. She was in despair as she sought to provide him excellent nutrition, deal with his frustration at being denied some of his beloved foods, and try to make sense of the advice she was given by the nurse at the pediatric office. She had been simply told not to give him any of these foods until she could make an appointment with the allergist.
I asked her why the tests had been run. She stated that her son had had mild to moderate eczema for several years and recently had over a week of hives that led to the test being done. She had no idea he was so allergic to so many foods.
As I reviewed the tests with her it became clear to me that all of the positive tests were of the IgG4 type. These tests are not approved for the detection of allergic response by the body. The serum IgE tests were negative to all foods. Some of the environmental IgE tests were positive such as dust mite and cat dander. The celiac tests were negative as well. I was troubled at the use of testing methods that were not approved for allergy evaluation. I was also troubled by the misuse of such tests to alter diet and lifestyle unnecessarily. No testing was indicated at all by the history and therefore the financial cost and family turmoil could have been avoided.
The National Institute of Allergy and Infectious Disease (NIAID) released the first ever Guidelines for the Diagnosis and Management of Food Allergy last week (http://www.niaid.nih.gov/topics/foodallergy/clinical/Pages/default.aspx). The intent of the guideline is to assist clinicians in properly diagnosing and managing food allergy. The recommendations are based on studies and expert opinion both. They address both recommended and controversial methods of testing for allergy. It addresses dietary advice for both the allergy sufferer and family members. It addresses proper emergency management techniques and medications. Finally the guideline recommends that patients with suspected food allergy see a specialist who can look at all the facets of the problem: the history, the exam, and the testing results. Food challenges can sometimes also be helpful in understanding the relevance of skin or specific IgE blood testing. In early 2011 the NIAID will release a lay person version of the food allergy guidelines. We will post the link here when it is available.
After our lengthy conversation about the facts of food allergy and testing mother and son were excited to have his favorite foods restored to him. After reviewing the facts surrounding his rash we decided that his outbreak of hives was likely due to a cold virus he suffered around the same time. She called the office today to report that he is doing well, eating all his favorite foods, and enjoying being a normal boy again.