Abstract
BACKGROUND: Baked egg is tolerated by a majority of egg-allergic children. OBJECTIVE: To characterize immunologic changes associated with ingestion of baked egg and evaluate the role that baked egg diets play in the development of tolerance to regular egg. METHODS: Egg-allergic subjects who tolerated baked egg challenge incorporated baked egg into their diet. Immunologic parameters were measured at follow-up visits. A comparison group strictly avoiding egg was used to evaluate the natural history of the development of tolerance. RESULTS: Of the 79 subjects in the intent-to-treat group followed for a median of 37.8 months, 89% now tolerate baked egg and 53% now tolerate regular egg. Of 23 initially baked egg-reactive subjects, 14 (61%) subsequently tolerated baked egg and 6 (26%) now tolerate regular egg. Within the initially baked egg-reactive group, subjects with persistent reactivity to baked egg had higher median baseline egg white (EW)-specific IgE levels (13.5 kU(A)/L) than those who subsequently tolerated baked egg (4.4 kU(A)/L; P= .04) and regular egg (3.1 kU(A)/L; P= .05). In subjects ingesting baked egg, EW-induced skin prick test wheal diameter and EW-, ovalbumin-, and ovomucoid-specific IgE levels decreased significantly, while ovalbumin- and ovomucoid-specific IgG(4) levels increased significantly. Subjects in the per-protocol group were 14.6 times more likely than subjects in the comparison group (P< .0001) to develop regular egg tolerance, and they developed tolerance earlier (median 50.0 vs 78.7 months; P< .0001). CONCLUSION: Initiation of a baked egg diet accelerates the development of regular egg tolerance compared with strict avoidance. Higher serum EW-specific IgE level is associated with persistent baked and regular egg reactivity, while initial baked egg reactivity is not.