What to do about all those positive food allergy test results- The New Food Allergy Guidelines-2010

Undoing some of what has already been done?

Our Indianapolis Star posted a story from Shari Roan. Ms Roan is reporter for the Los Angeles Times. The title of the article in the Star was ‘You may be allergic to a food . . . or not’ . The original article by Ms. Roan had a slightly different title.

The article coincided with the announcement of the publications of the ‘New Guidelines for the Diagnosis and Management of Food Allergy’. This document represented the efforts of a group of food allergy experts working with the National Institute of Allergy and Infectious Diseases. In one of my earlier posts I commented on a draft of this document. The final product is now available.

What struck me after reading the article was the need for us to undo what has been done. There are  many children out there who have had extensive food allergy testing performed and struggle with numerous positive food allergy test results. Are they all truly allergic to all those foods? Are they being deprived of adequate nutrition? Can we help them and their families?

‘A lot of physicians order large numbers of blood tests of various foods, and when they find small amounts of antibody present, they indicate to the patient  that they are allergic to this food and should not ingest it,’ according to Dr. Hugh Sampson- an internationally recognized expert in food allergy. The article goes to state that many children are placed on highly restricted diets that are probably not necessary.

It is also important to point out that the same consequence can be seen with the results of skin testing.

The New Guidelines state that oral food challenges will be needed to sort out the relevance of the positive food allergy test. The oral food challenge is required to make an accurate diagnosis. These guidelines point out that a positive test result only shows sensitization. The test result must be used together with a history for a correct diagnosis of food allergy.

Stated a bit more firmly, these New Guidelines advise against making the diagnosis of food allergy solely based on the results of skin prick tests or blood tests.

 I foresee pediatric allergy practices becoming more involved with doing food challenges. A child presents with an array of positive food allergy tests, restrictive dietary advice, and accompanied by scared and frustrated parents. All too often many of the foods they have been told to avoid had been eaten with impunity- there was absolutely no observed reactions with ingestion, but there was a positive allergy test. This is very confusing.

In  pediatric allergy we sort through the history of exposure and the appearance of reactions that are IgE-mediated (the antibody detected by food allergy testing). We look for that constancy of cause/effective relationships with the food. We also need a sense of the timing between exposure and reaction. From that history, the proper selection of food allergy tests is then made.

So now we need to verify clinical reactivity to food allergy test results that revealed sensitization. For some foods we have been given guidance regarding the chance of having a reaction. For many other foods we do not have that information. Many of these challenges will be adventures in uncharted waters. In our practice we have done many challenges for milk, egg, soy, wheat, and peanut. We have also challenged to beef.  For the other foods we can put together a protocol for the safe introduction of a ‘challenge’ food.

Take a look at these New Guidelines for the Diagnosis and Management of Food Allergy.

FEL

December 10, 2010 · fleickly · 2 Comments
Tags: , ,  · Posted in: Allergies, Allergy Testing, Egg Allergy, Food Allergies, Guidelines for the Diagnosis and Management of Food Allergy

2 Responses

  1. Angi - July 8, 2011

    Hi Dr. Leickly. I was directed to this site some time ago by Anita Rigel for my oldest son who suffers from eczema. My question today pertains to my youngest son, though. He was born at 34 weeks, and is now 1 year old. He was diagnosed with milk protein intolerance at one month old and still can not tolerate dairy (all GI symptoms). He received his 12 month vaccines on Wednesday, which included the MMR, and about 24 hours after, he had bloody mucusy poo for about 12 hours. He continues to have diarrhea, but the blood has cleared. Have you heard of such a reaction from vaccines before? Do you think this could possibly be a reaction to egg? He is still on baby food, so his exposure to egg is extremely minimal.
    Thanks for any insight you may have.
    Angi

  2. fleickly - July 17, 2011

    Thank you for watching the site and submitting a question.
    Now milk protein allergy may mean different things and it depends which specialty is using the term. I hear this from primary care and gastroenterologists when they are referring to the occurence of blood in the stool due to milk. An allergist knows that the allergen is a protein- not a sugar, not a fat. Milk allergy would be hives, atopic dermatitis, immediate vomiting, immediate diarrhea, and anaphylaxis.
    Blood in the stool would not be a type one (IgE) mediated condition due to a food or other trigger. The classical, type 1, IgE reactions are bloodless (unless a child with nasal allergy picks the nose too much). This sounds as if it was possibly some other immune mechanism, however there are usually no tests available for such reactions. The milk protein entercolitis is a clinical diagnosis- blood in the stool due to milk (there are other foods), we would have no diagnositics that that- Pediatric GI would be the best source for help. Blood in the stool due to an immuniztion- I have not come across that.
    Now the MMR has not been a worry in the egg allergic population. The other egg contain vaccines are influenza and yellow fever-no I do not think it was due to an allergic reaction to egg in the vaccine. Run this by your pediatrician. My guess is that a pediatric GI consult would be considered.
    FEL