The natural history of egg allergy

Background

Egg allergy is very common, affecting 1% to 2% of children. It is generally thought that the majority of children with egg allergy develop tolerance in early childhood; however, this has not been examined in a large cohort with egg allergy.

Objective

The purpose of the study was to estimate the proportion of children with egg allergy who develop egg tolerance and to identify predictors of tolerance development.

Methods

Retrospective chart review of patients with egg allergy seen in a tertiary referral clinic. Patients were considered to have developed egg tolerance if they tolerated concentrated egg.

Results

Kaplan-Meier analysis predicted resolution in 4% of patients with egg allergy by age 4 years, 12% by age 6 years, 37% by age 10 years, and 68% by age 16 years. Patients with persistent egg allergy had higher egg IgE levels at all ages to age 18 years. A patient's highest recorded egg IgE, presence of other atopic disease, and presence of other food allergy were significantly related to egg allergy persistence.

Conclusion

A majority of patients with egg allergy will develop egg tolerance, although the rate of tolerance development is slower than described previously. Egg IgE is predictive of allergy outcome and should be used in counseling patients on prognosis.

Clinical implications

Most patients with egg allergy are likely to develop egg tolerance by late childhood, with the exception of patients with an egg IgE greater than 50 kU/L, who are unlikely to develop egg tolerance.

Key words: Egg, egg allergy, food allergy, IgE, tolerance, natural history

Abbreviation used: SPT, Skin prick test