U.S. Experts Release Food Allergy Guidelines
Diagnosis and Testing: The guidelines stress the difference between a sensitization to a food and a true allergy. Sensitization to a food means a person’s body creates antibodies against it; however, it does not necessarily indicate that a person will have allergic symptoms when they eat the food.
This means, according to the expert panel, that certain tests, such as a skin prick test, should not be used alone to diagnose food allergy. Rather, family history and a history of reactions must be carefully evaluated.
According to the guidelines, the only way to definitely diagnose a food allergy is an oral food challenge. This type of test involves the person eating a gradually increasing amount of their allergen in a medically supervised setting. If the person begins to have allergic symptoms, then the diagnosis is positive. If there’s no reaction, then it’s negative.
(In certain circumstances, an oral food challenge might not be needed. For example, if a toddler has an anaphylactic reaction upon their first taste of peanut butter, Sampson told Allergic Living he would likely not do an oral food challenge, as long as a skin prick test or blood test confirmed the child is sensitized to the suspected food.)
Sampson said in the conference call that oral food challenges are underused, because the process is lengthy and it puts the patient at risk of anaphylaxis.
However, when it’s not used, many people are diagnosed with food allergies that they don’t actually have, and are put on highly restrictive diets unnecessarily.
“We see a lot of physicians ordering blood tests, a large number of blood tests to various foods, and when they find small amounts of antibodies present, tell individuals they’re allergic to foods and shouldn’t ingest them. This has led to a number of children that are put on highly restrictive diets. When we see them and go through the challenge procedure, they don’t react to many of [the foods]” he says.
The guidelines also indicate which tests are not recommended at all in the diagnosis of food allergies. This includes intradermal tests, total serum IgE tests and atopy patch. A list of non-standardized and unproven tests is also provided.
Treatment: The guidelines state that an epinephrine auto-injector is the first line of defence against an anaphylactic reaction. The life-saving medication should be used at the first sign of an anaphylactic reaction and the person should be brought to the emergency room of a hospital for further treatment and monitoring.
“We recommended that individuals [at risk of anaphylaxis] have some sort of auto-injector with epinephrine with them at all times,” says Sampson, adding that other drugs, such as anti-histamines and corticosteroids, are secondary medications.
Maternal and Infant Diets: The guidelines also address maternal and infant diets as a way to prevent food allergy. Many studies have looked at what pregnant and breastfeeding mothers are eating, as well as when infants are introduced to foods, in an effort to find a correlation to the development of food allergies.
However at this time, the NIAID guidelines mirror what is currently advocated by the American Academy of Pediatrics. Specifically, the guidelines state:
- that restricting the maternal diet during pregnancy or lactation as a strategy for preventing the development or clinical course of food allergy is not recommended.
-that all infants be exclusively breast-fed until 4 to 6 months of age, unless breastfeeding is contraindicated for medical reasons.
- that the introduction of solid foods should not be delayed beyond 4 to 6 months of age. Potentially allergenic foods may be introduced at this time as well.