Allergy Fast Facts

The American Academy of Pediatrics (AAP) puts out a newsletter each month (AAP News). This month there was a few inserts; one dealing with the 2012-2013 Influenza Vaccine Guidelines and the other was ‘Fast Facts on Allergy Testing’. ‘Fast Facts’ was written by Dr. Scott Sicherer for the AAP Section on Allergy and Immunology. This is something primary caretakers and parents need to know about.

The title is ‘Fast Facts on Allergy Testing What you need to know, based on the AAP Clinical Report entitled, Allergy Testing in Childhood: Using Allergen-Specific IgE tests (found in Pediatrics 2012;129(1):193-7).

Fast Fact 1. Treatment decisions for infants and children with allergy should be made on the basis of history and when appropriate, identified through directed serum sIgE or skin prick tests (SPT). Newer in vitro allergen-specific serum IgE (sIgE) tests have supplanted radioallergosorbent tests (RASTs).

Fast Fact 2. Allergy tests for sIgE must be selected and interpreted in the context of a clinical presentation; test relevance may vary according to the patient’s age, allergen exposure, and performance characteristics of the test.

Fast Fact 3. Positive sIgE test results indicate sensitization, but are not equivalent to clinical allergy. Panels of indiscriminately performed screening tests may therefore, provide misleading information.

Fast Fact 4. Tests for sIgE may be influenced by cross-reactive proteins that may or may not have clinical relevance to disease.

Fast Fact 5. Increasingly higher levels of sIgE (higher concentrations on serum tests or SPT wheal size) generally correlate with an increased risk of clinical allergy, but increasing sIgE tests typically do not reflect severity of allergies.

Fast Fact 6. Use of a multiallergen serum test can be helpful for screening for atopic disease if there is a clinical suspicion. If positive, allergen specific testing may be considered.

Fast Fact 7. Tests for allergen-specific IgG antibodies are not helpful for diagnosing allergies.

Fast Fact 8. Because test limitations often warrant additional evaluation to confirm the role of specific allergens, consultation with a board-certified allergist-immunologist should be considered.

The bane of a pediatric allergy practice is that child and his/her very frustrated family that has spent time and money (panels can cost $2500) and who has anguished over misleading tests or even the wrong test results and the recommendations made based on those tests. Every week I see at least one child who unfortunately has had IgG to foods performed. Almost every day I have at least one new child who has had some form of an allergy panel run. I have often thought my role has become somewhat of a sheriff- sorting out proper histories of cause/effect relationships, disarming recommendations made based on potentially invalid tests, and trying to educate families about allergy, allergy testing, and the nuances of our specialty. Allergy especially pediatric allergy is still one of those specialties in which the story has to be told and understood. Tests are not the sine qua non- and no test makes any child allergic. Appropriate tests are done to validate a clinical impression.

I applaud Dr. Sicherer, the AAP, and the Allergy Section of the AAP for putting this together. What follows could be the faster Fast Facts;

Let the history dictate the choice of tests.

Don’t call it RAST.

Do the tests for the right reasons –conditions known to be allergy IgE driven.

You can test at any age, the problem is what you test for that may vary due to age.

A positive allergy test just indicates sensitization not necessarily allergy

Panels can be misleading- do not do them.

Tests can be positive due to cross-reactivity and not be related to a condition.

The size of a test is not related to how allergic the child is.

IgG tests for food allergy are worthless.

See a board-certified pediatric allergist-immunologist for your child.

FEL (10-3-12).

October 10, 2012 · fleickly · No Comments
Tags: , ,  · Posted in: Allergies, Allergy in Children, Allergy Testing, Article Review, Choosing wisely, Interesting articles, Phadia Allergy Tests