New Allergy Testing Guidelines

Allergy blood and skin prick tests should not be solely for diagnosis

(RxWiki News) Allergy testing is a common practice to determine a child's allergy. A new advisory is cautioning pediatricians against using the test solely to diagnose allergies.

Blood tests and skin-prick tests are vital tools for a pediatrician in helping to diagnose childhood allergies, however these two tests should not be used alone to to diagnosis an allergy.

Pediatricians should take into account a child's medical history and other factors in addition to the two tests.

"Ask your pediatrician if allergy testing is needed."

The allergy testing advisory was written by allergists Dr. Robert Wood of the Johns Hopkins Children’s Center and Dr. Scott Sicherer of Mt. Sinai Hospital in New York. The allergists issued the advisory to help pediatricians better treat childhood allergies and reduce possible misdiagnosis.

The allergists recommend not using the tests to try and diagnose allergies in children who do not display any allergic symptoms. For food allergies, it is recommend to undergo a food challenge, where a child eats a small amount of the suspected food while being medically supervised.

Blood testing and a skin-prick test can only evaluate the level of the IgE antibodies. IgE antibodies are chemicals that are released by the immune system in an allergic response. It can help detect if a person is sensitive to allergens but not if they will actually have an allergic reaction to the suspected allergen.

A perfect example of this is the diagnosis of peanut allergies in children. According to the study, previous research has shown that eight percent of children will test positive to a peanut allergy from a skin or blood test.

Out of this eight percent, only one percent will display actual allergic reaction and clinical symptoms.

That is not to say that the tests should be abandoned. Allergies that go undiagnosed can be deadly, according to Drs. Wood and Sicherer. But relying too heavily on the tests that can lead unnecessary food and environmental restrictions, such as getting a pet.

These tests can still be used for a number of cases. A child with moderate to severe asthma could have these tests performed to determine sensitivity to irritants such as dust mites, mold, pollen, pet dander or cockroaches.

Periodically monitor an established food allergy and determine if the IgE antibodies have decreased which means the child may have outgrown the allergy.

Insect venom allergies can also be confirmed using a blood or skin test. A skin test can also be used to determine a vaccine allergy. 

A blood or skin test should not be used as a way to test for an allergy in a child who does not display any allergy symptoms or drug allergies. In addition, children who have established food allergies should not undergo testing as it will not add any new insight.

Childhood allergies are serious and parents as well as pediatricians take care to try and diagnose possible allergies. Skin and blood tests are important tools that should be used but only with caution and within the proper context.

This advisory was published in the January edition of Pediatrics.

Reviewed by: 
Review Date: 
December 29, 2011