70% of Egg Allergic Children Tolerate Extensively Heated Egg
Egg allergies are one of the most common childhood food allergies. Many of us were told that our egg- allergic children would outgrow this allergy by age five or six, but studies have shown that egg allergy today persists much longer. Recent studies have demonstrated that some egg-allergic children can tolerate egg in extensively heated baked goods like cookies and cakes. Researchers led by Dr Anna Nowak-Wegrzyn from the Mount Sinai School of Medicine in New York studied 117 children who had a confirmed egg allergy and found that 70% were able to tolerate extensively heated egg in muffins or waffles. Research is ongoing and hopefully someday soon we will know if ingesting extensively heated egg may help to induce tolerance verses continued avoidance.
Parents are strongly cautioned against experimenting at home. Although many children were able to tolerate extensively heated egg, a significant portion had severe reactions.
Gina Clowes: What ages were the children in this study?
Anna Nowak-Wegrzyn : Mean age was 6.9 years, from 1.6 to 18.6 years
GC: Did it include children who had suffered from anaphylaxis to egg?
ANW: Yes, past history of anaphylaxis was not an exclusion criterion and we found no difference in rate of anaphylaxis between those who reacted or tolerated baked egg.
Was age or sex a factor? Were older or younger children more tolerant of baked or cooked egg?
ANW: No, we found no differences in children less than 5 and older than 5 years in the rate of tolerating baked egg.
Was the presence of asthma, eczema or other allergies a factor in predicting tolerance to baked egg?
ANW: No
Was egg specific IgE or total IgE level a factor in predicting tolerance to baked egg?
ANW: No, egg white specific IgE was not helpful. We did not look at total IgE as this is very non-specific. Only food challenge was able to identify those children tolerant to baked egg.
Could rast tests or skin tests predict who would be able to tolerate baked egg in the initial challenge?
ANW: Not very helpful.
Did you exclude children with a rast score over any certain level?
ANW: No, children were not excluded based on egg white IgE level.
What can you tell us about those who tolerated baked egg vs those who did not?
ANW: Those who reacted to baked egg had significantly larger egg white skin test wheal diameters, and greater egg white, ovalbumin and ovomucoid (specific proteins in egg white)-specific IgE antibody levels than those who tolerated baked egg. They were not different in regard to any clinical characteristics.
Can you tell us a little more about the study? When an egg-allergic child was able to tolerate baked egg, but not cooked egg, how often did they have to include it in their diet?
ANW: Children who tolerated baked egg were told to eat 1- 3 servings per day of baked products with egg.
Did you observe anxiety or stress in the children or parents when they were told to incorporate baked egg into their diet?
ANW: No, the majority enjoyed having fewer restrictions. It was difficult for one child to eat baked products with egg everyday because she was not used to having baked goods and she withdrew from the study.
How significant were the drops in the allergy test results for the children who continued to consume baked egg for 12 months?
ANW: We saw statistically significant decrease in the size of skin test to egg white and increases in ovomuycoid and ovalbumin IgG4 antibody (antibodies thought to be associated with development of tolerance) levels from baseline to 3 months, those differences were maintained at later time points. We saw no significant change in egg white IgE at any time point.
Were any of the results negative?
ANW: We did not see any negative effect of the baked egg ingestion on growth or allergic diseases such as eczema, asthma or allergic rhinitis. We also looked at the intestinal permeability and found no effect. We are still evaluating the effect of baked egg ingestion on the rate of outgrowing egg allergy (development of tolerance to regular egg).
How was the initial baked challenge conducted?
ANW: The initial challenge was conducted carefully under strict supervision. We found that although 70% of tested children tolerated baked egg, some of those who reacted to baked egg (about 20%) experienced systemic reactions (anaphylaxis) that were treated with epinephrine. Considering that skin tests or specific IgE levels are not predictive of tolerance to baked egg, introduction of baked egg should only be done under physician supervision. We still don’t the know how eating baked egg affects resolution of egg allergy.
Is this research ongoing?
ANW: We continue to follow the children and will be publishing more data.
Anna Nowak- Wegrzyn, MD is an assistant professor of pediatrics at the Mount Sinai School of Medicine in New York Her research interests focus on the mechanisms of outgrowing egg and milk allergy, “oral allergy syndrome” and food protein-induced syndrome (FPIES).
