The impact of food matrices on egg allergenicity

Although many studies show the impact of high and prolonged heating on allergenicity, scarce research exists that examined the impact of the food matrix effect. We presented a case that demonstrates the need for further investigation into this field.

An 8-month-old breast-fed girl with a history of moderate eczema presented with concern for food allergy. At 7 months old, she seemed to have difficulty with nursing after consumption of peanut butter, and her pediatrician recommended further avoidance. On presentation to allergy, she had not yet consumed eggs; therefore, skin testing was obtained for both peanut and egg. Her skin testing result to peanut was negative, whereas to egg was elevated at 5/20 mm. To further support clinical decision-making, blood work was obtained, and the egg white specific immunoglobulin E (IgE) value was elevated to 1.33 kU/L. It was recommended to the family to pursue home introduction of peanut and return for oral challenge to baked egg. At 14 months old, the patient returned for oral challenge and successfully tolerated one-half of a muffin. She was discharged with instructions to continue consumption of one-half of a muffin ideally three or more times a week, which the parents reported she continued to tolerate.

When the patient was 24 months old, the mother decided, without consultation, to introduce banana-chocolate chip muffins. With the first two ingestions, she developed immediate urticaria. On the third consumption, she developed anaphylaxis, which required epinephrine, with rapid improvement. The patient subsequently returned to regular consumption of standard egg muffins (as well as bananas and chocolate individually), which she continued to tolerate. Based on our patient's ability to tolerate baked egg muffins without banana but significant reaction to baked egg muffins with banana, a potential explanation is that the addition of banana disrupted the egg-wheat matrix. This report points toward a continued need to investigate the role food matrices play on the allergenicity of foods. Furthermore, this case demonstrated the importance of adhering to allergist-prescribed recipes to prevent allergic reactions.