Baked egg tolerance: is it possible to predict?

Baked milk and egg diets revisited

Most children with milk and egg allergy are nonreactive to modified forms of milk and egg in bakery products such as muffins because of conformational changes in proteins. These baked milk (BM) and baked egg (BE) diets have become commonplace in the management of milk and egg allergy, respectively. Current laboratory- and skin test-based diagnostic approaches remain limited in their ability to predict BM/BE tolerance, resulting in various approaches to introduce these foods. One approach to introduce BM/BE is to offer a medically supervised oral food challenge and then advise dietary introduction of baked products for children who have tolerance. Another approach is adapted from a home-based protocol of graded ingestion of BM or BE originally intended for non-IgE mediated allergy, often referred to as a "ladder." The ladder advises home ingestion of increasing amounts of BM or BE. For children who have allergy to BM or BE, the ladder is essentially oral immunotherapy, although not always labeled or recognized as such. Risk assessment and education of patients suitable for home introduction are essential. A home approach that may be called a ladder can also be used to escalate diets after demonstrated tolerance of baked forms by introducing lesser cooked forms of milk or egg after tolerating BM or BE. A randomized controlled trial provided clear evidence that baked diets can hasten the resolution of IgE-mediated milk allergy. Moreover, BM/BE foods have an emerging role in the treatment of non-IgE-mediated allergy. There is tangential evidence for BM and BE diets in the prevention of IgE-mediated allergy.

Pediatric oral food challenges in the outpatient setting: A single-center experience

Background

Oral food challenge (OFC) is the criterion standard for diagnosing food allergy (FA). It is important to have parameters to aid in selecting ideal OFC candidates.

Objective

We sought to characterize outcomes and predictors of OFCs for common food allergens.

Methods

We completed a retrospective chart review of all OFCs for IgE-mediated FA performed at Duke University pediatric allergy clinics from June 2017 through May 2022. Patients were deemed eligible for milk, egg, and nut OFC if testing revealed a specific IgE level not exceeding 2 kU/L and a skin prick test (SPT) resulting in a wheal size not exceeding 5 mm. Different parameters were followed for selecting candidates for baked challenge.

Results

A total of 663 OFCs were conducted on 510 patients (59% male). The most common foods challenged were peanut (26%), plain egg (23%), baked egg (8%), and milk (8%), with pass rates of 84%, 88%, 62%, and 84%, respectively. Of the patients who failed OFC, 84% had objective symptoms, 23% had multisystemic reactions, and 15% required epinephrine. Although the presence of a personal or family history of atopy or prior failed OFC was not associated with outcomes, a history of anaphylaxis (regardless of the trigger) was associated with increased risk of failure.

Conclusion

Although there are no established consensus guidelines, our study provides a benchmark illustrating that cutoffs of a specific IgE level not exceeding 2 kU/L and SPT finding not exceeding 5 mm result in a failure rate of approximately 13% for nonbaked milk, nonbaked egg, and nuts. The high rate of failed baked egg OFCs is likely related to selection bias, but our results illustrate the low negative predictive value of ovomucoid.

Baked Milk and Baked Egg Survey: A Work Group Report of the AAAAI Adverse Reactions to Foods Committee

Most milk- and egg-allergic children can tolerate milk and egg in baked forms. Some allergists have extended the use of baked milk (BM) and baked egg (BE) to advocating for the stepwise introduction of small amounts of BM and BE to children who are reactive to larger amounts of BM and BE. Little is known about the practice of introducing BM and BE and existing barriers to this approach. The purpose of this study was to gather a current assessment of the implementation of BM and BE oral food challenges and diets for milk- and egg-allergic children. We conducted an electronic survey of North American Academy of Allergy, Asthma & Immunology members offering BM and BE introduction in 2021. The response rate was 10.1% of distributed surveys (72 of 711). Surveyed allergists had a similar approach to both BM and BE introduction. Demographic features of time in practice and region of practice were significantly associated with the odds of introducing BM and BE. A wide variety of tests and clinical features guided decisions. Some allergists determined BM and BE to be appropriate for home introduction and offered this for BM and BE more often than other foods. The use of BM and BE as a food for oral immunotherapy was endorsed by almost half of respondents. Less time in practice was the most significant factor associated with offering this approach. Published recipes were used and written information was widely provided to patients by most allergists. The wide practice variabilities reveal a need for more structured guidance about oral food challenges, in-office versus home procedures, and patient education.

Guided Gradual Egg-Tolerance Induction in Hen's Egg Allergic Children Tolerating Baked Egg: A Prospective Randomized Trial

Background

Over the last few years, studies have shown that the majority of egg allergic children tolerate baked egg (e.g., cake), and that consuming baked egg accelerates the resolution of egg allergy. However, few prospective studies demonstrate the step-wise reintroduction of egg at home after developing baked egg tolerance. Although this could have a positive impact on the children's quality of life and nutrition. Additionally, research supporting the theoretical concept that heating in the presence or absence of wheat causes reduced allergenicity of egg proteins is limited.

Objective

To investigate the clinically most favorable duration of gradual egg-tolerance induction in baked egg tolerant children at home, with regard to complete raw egg tolerance.

Methods

Baked egg tolerant children above 12 months of age were randomly assigned to a short- or long arm protocol. In the short arm, egg-tolerance induction was studied over 18 months compared to 30 months in the long arm. Children were guided through this protocol involving the step-wise introduction of increasingly allergenic forms of egg starting with baked egg offered as cake, followed by hard-boiled egg, omelet/waffle/pancake, soft-boiled egg, and finally raw egg. We hereby designed this protocol based on the influence of thermal processing in the presence or absence of wheat on egg proteins, as investigated by ELISA, SDS-PAGE, and immunoblotting. At inclusion, children either passed an in-hospital cake challenge or had ovomucoid sIgE ≤1.2 kUA/L, which was considered safe for introduction at home.

Results

Gel electrophoresis revealed that the ovalbumin band became weaker with heating, while the ovomucoid band remained stable. In accordance, the IgE-binding to ovalbumin decreased with extensive heating, as opposed to ovomucoid. However, heating in the presence of wheat led to a decreased IgE reactivity to ovomucoid. Of the 78 children in the intention-to-treat group, 39 were randomized to each arm. Fifty-eight children reached the raw egg tolerance endpoint, of which 80% were in the short arm and 69% in the long arm. Within the short arm, the median time to raw egg tolerance was 24 months (95% CI, 21–27 months) compared to 30 months (95% CI, 28–32 months) in the long arm (p = 0.005). No grade IV reactions or cases of eosinophilic esophagitis were observed. The short arm was considered to be non-inferior to the long arm.

Conclusion

Our gradual short arm protocol appears to be safe and allows clinicians to guide baked egg tolerant children toward raw egg tolerance at home. The allergenicity of the egg proteins was affected by heating temperature and duration, as well as the presence of wheat.