Immunologic changes in children with egg allergy ingesting extensively heated egg

Background

Prior studies have suggested that heated egg might be tolerated by some children with egg allergy.

Objective

We sought to confirm tolerance of heated egg in a subset of children with egg allergy, to evaluate clinical and immunologic predictors of heated egg tolerance, to characterize immunologic changes associated with continued ingestion of heated egg, and to determine whether a diet incorporating heated egg is well tolerated.

Methods

Subjects with documented IgE-mediated egg allergy underwent physician-supervised oral food challenges to extensively heated egg (in the form of a muffin and a waffle), with tolerant subjects also undergoing regular egg challenges (in a form of scrambled egg or French toast). Heated egg–tolerant subjects incorporated heated egg into their diets. Skin prick test wheal diameters and egg white, ovalbumin, and ovomucoid IgE levels, as well as ovalbumin and ovomucoid IgG4 levels, were measured at baseline for all subjects and at 3, 6, and 12 months for those tolerant of heated egg.

Results

Sixty-four of 117 subjects tolerated heated egg, 23 tolerated regular egg, and 27 reacted to heated egg. Heated egg–reactive subjects had larger skin test wheals and greater egg white–specific, ovalbumin-specific, and ovomucoid-specific IgE levels compared with heated egg– and egg-tolerant subjects. Continued ingestion of heated egg was associated with decreased skin test wheal diameters and ovalbumin-specific IgE levels and increased ovalbumin-specific and ovomucoid-specific IgG4 levels.

Conclusions

The majority of subjects with egg allergy were tolerant of heated egg. Continued ingestion of heated egg was well tolerated and associated with immunologic changes that paralleled the changes observed with the development of clinical tolerance to regular egg.

Key words: Egg allergy, hen's egg allergy, baked egg, heated egg, food allergy, intestinal permeability, oral food challenge

Abbreviations used: LacMan, Lactulose/mannitol ratio, SPT, Skin prick test