Allergy Notes makes some good observations about oral food challenges (OFC) in his article, "85% of Allergists perform Gold Standard Test for Diagnosis of Food Allergy". He points out that fewer than 6% of allergists perform more than 10 per month, citing time, insurance reimbursement and risk of adverse reactions as the reasons for conducting so few OFC's.of
For several years food allergic patients have been told that OFC's are the most definitive method to test food allergies. More commonly however, skin prick tests and blood tests are used by allergists to determine food allergy. Our personal experience has shown that the results of these two common allergy tests may not provide definitive results. Skin tests on a person with eczema and/or sensitive skin is often of little value. Certain people react to nearly anything pricked into their skin and the blotchy red welts that result make it appear that the person is allergic to everything.
The next test for food allergies is blood work. I remember one visit to Children's Hospital with my then 2 1/2 year old. They told us to list any food we thought he might have an allergy to. We listed 30 foods we suspected.
The blood test results? Allergic to all.
Nonsense said our primary allergist as my child had been successfully eating many of these foods. We've had many inconclusive blood test results. Not only is blood work traumatizing to a child, but avoiding so many types of foods unnecessarily could lead to poor growth and nutrition.
We've now done about a dozen oral food challenges in the allergist's office now. They are very time consuming- taking between 3-4 hours typically. This makes it difficult to do during the school year (and who wants to give up a school holiday to sit in the allergist's office to eat something that may cause an allergic reaction?). There are three types of OFC's: open, single-blind and double blind. In the open challenge, everyone knows the suspected food is being given. This is the only type of challenge we've done. A single blind means the patient doesn't know if they are ingesting the offending food or a placebo, and in the double blind, the patient and the medical staff are unaware if it is the suspected food or a placebo. We have observed a huge psychological factor in these open
challenges in which the person may think there is tongue tingling or
thickness in the throat because they know the food may cause a reaction. We have also found over the years, OFC's have become more and more expensive to us as insurance companies have decreased reimbursement.
So, even OFC's still may not give the definite results we seek. Some of our challenges may have been halted prematurely by the allergist who was concerned about possible reactions. Sometimes we leave the OFC still not knowing for sure if there was a reaction. For now, though, it's the best test we've got and it does provide some clues that may be helpful to the food allergic person and their family.
In light of this, I hope to see more training of allergists and better reimbursement from insurance companies. Until we come up with something better, let's use OFC's to help those with food allergies determine what foods need to be avoided and what foods they need not fear.
Check out Oral Food Challenge Practices among Allergists in the United States from The Journal of Allergy and Immunology for more information.