I had a chance to ask my colleague Dr. Mike Pistiner what he thinks about the new food allergy guidelines.
Allergic Girl: Can you clarify the difference between sensitization and tolerance as it relates to food allergies?
Michael Pistiner, MD: The concepts of sensitization and tolerance can be tricky. As per the guidelines, sensitization is the presence of IgE that is made to a specific allergen. IgE is the class of immunoglobulin (antibody) that plays a role in immediate allergic reactions. Sensitization to a food is not the same thing as a food allergy. People can make specific IgE to a food without having any symptoms. Although specific IgE plays a role in the majority of allergic reactions, especially immediate ones, some food allergy is driven by the immune system but without involvement of IgE (non-IgE mediated allergy). To clarify, a person can be sensitized to a food but not allergic to it. Also, a person can have a non-IgE mediated food allergy without any detectable IgE.
The guidelines use the word tolerate to describe a situation where a person has either outgrown a food allergy or has received therapy and no longer experiences symptoms with that food. They define the specific term tolerance, as a being able to consume a food without any symptoms weeks to years after treatment is stopped.
AG: Where do you see the biggest leaps forward in the food allergy guidelines?
MP: Prior to the food allergy guidelines there had been little consistency in the approach to food allergies. Healthcare providers with different training and different geographic locations could approach food allergies in vastly different ways. These food allergy guidelines help provide a more uniform and coordinated approach. It will not only aid the individual health care provider during direct patient care, but also will assist in communication between providers, and aid in the accumulation of information used in research that will further guide future approaches.
AG: Where, if any, are there still gaps in knowledge?
MP: Available diagnostic testing is far from perfect. Although the food allergy guidelines recommend the use of skin prick testing and testing for specific serum IgE to assist in the diagnosis of IgE mediated allergy, relying on testing alone is not appropriate in the diagnosis of food allergy. Relying solely on these tests can result in missed cases of food allergy or over diagnosis of food allergy. Furthermore, the guidelines recommend NOT using non-standardized tests for the diagnosis of IgE mediated allergy (including, but not limited to: applied kinesiology, IgG testing, provocation neutralization, cytotoxic assays, electrodermal testing, mediator release assay, hair analysis, facial thermography, lymphocyte stimulation, basophil histamine realease/activation, gastric juice analysis, and endoscopic allergen provocation).
AG: Were you surprised by any of the food allergy guidelines findings?
MP: No I wasn’t. The lack of consistent terminologies and approaches to food allergy, limitations in diagnostic testing, and the fact that there is no current treatment, makes caring for those with food allergy a real challenge. The food allergy guidelines support the critical importance of taking the whole picture in the approach to a food allergy (for example: using history and physical exam, available standardized testing (skin prick and/or specific serum IgE), physician directed food challenges and elimination diets) and the importance of effective communication and education.
AG: What important point will you underscore to your food allergy patients as it relates to definitions, diagnosis or treatment of food allergy?
MP: I will encourage them to hang in there. There are still many unanswered questions when it comes to food allergy. We all need to get comfortable with this. Now, with more uniform definitions and approaches we will have a solid base to build upon. With time, more and more evidence will accumulate. Until then we need to get comfortable with what we do know and keep coping, always.
Dr. Pistiner practices at Northeast Allergy, Asthma, and Immunology and volunteers as a clinical instructor at Children’s Hospital Boston, Harvard Medical School. He is a food allergy educator and advocate and the author of Everyday Cool with Food Allergies.