Specific IgE levels as an outcome predictor in egg-allergic children.

Background: Diagnosis of immunoglobulin E (IgE)-mediated egg allergy is often based on both a compatible clinical history and either elevated IgE levels or a positive skin prick test. However, the gold standard is the oral food challenge (OFC). Previous studies have pointed to a correlation between IgE levels and OFC outcomes.

Objective: This study aimed to determine the relationship between IgE levels and the outcome of OFC, seeking to establish cut-off OFC values that indicate a high likelihood of positive OFC results.

Methods: A total of 198 patients who underwent OFC (and a serological IgE antibody assay within the three preceding months) were reviewed and divided by OFC type (i.e., baked, cooked, or raw egg). IgE-specific levels were assessed against the challenge outcome as well as cut-offs proposed by other authors.

Results: Receiver-operating characteristic (ROC) curve analysis yielded a potentially useful ovomucoid IgE-specific cutoff used in OFC with cooked egg and several egg white and ovalbumin IgE-specific cut-offs for OFC with raw egg. We found no significant relationship between other specific IgE concentrations and the challenge threshold level with baked eggs.

Conclusions: IgE-specific concentrations are useful as predictors of OFC outcome and should be considered when selecting patients challenge testing with boiled or raw egg. However, patients should undergo OFC with baked egg regardless of IgE levels.