If your child accidentally eats the food they avoid, will their food allergy last longer? What about purposely eating the food during an in-office food challenge? Have you avoided in-office food challenges because you’re afraid a reaction will make the allergy worse? A recently published study can put your mind at ease.
What the study was about
Researchers followed a group of 512 infants allergic to milk and egg. These babies also had a strong likelihood for peanut allergy. The researchers wanted to know what would happen if the children ate a small amount of allergen. Would this have an impact on their food allergy skin tests and blood tests?
What the study showed
The study included two groups of children. Some had oral food challenges (OFCs) that exposed them to their allergen. Some accidentally ate the food. Researchers looked at these children’s “before” and “after” skin and blood test results.
The results: These small exposures to allergens did not appear to make the allergy worse. There were no major differences in IgE levels or skin prick wheal sizes after oral food challenges. The same was true after children accidentally ate a small amount of milk, egg or peanut.
However, the researchers noted an important point about the study. The study only looked at short exposures to the food allergen, not repeated exposures.
Understanding the food allergy tests used in the study
The study used skin prick tests (SPT) and blood tests to evaluate the children’s food allergies. These tests detect the presence of specific immunoglobulin E (IgE) towards a specific food.
For skin prick tests, a drop of allergen is placed onto the skin surface. Then the skin is pricked so that the allergen goes into the top layer of the skin. If specific IgE antibody to the allergen is present, you’ll see an itchy bump and surrounding redness. The bump and redness is known as a wheal and flare.
IgE blood tests measure levels of specific IgE in the blood.
An oral food challenge in a medical setting is the “gold standard” of food allergy diagnosis. The patient eats small, but increasing, amounts of the suspect food to see if a reaction happens.
The study was published in the December 21, 2015 edition of Journal of Allergy and Clinical Immunology: In Practice.