A randomized trial of egg introduction from 4 months of age in infants at risk for egg allergy

Background: Epidemiological evidence suggests delayed introduction of egg may not protect against egg allergy in infants at risk of allergic disease. Objective: To assess whether dietary introduction of egg between 4-6 months in infants at risk of allergy would reduce sensitization to egg. Methods: We conducted a randomized controlled trial in infants with at least one first-degree relative with allergic disease. Infants with a skin prick test to egg white (EW-SPT) <2mm were randomized at age 4 months to receive whole-egg powder or placebo (rice powder) until 8-months of age, with all other dietary egg excluded. Diets were liberalized at 8-months in both groups. The primary outcome was EW-SPT ≥3mm at age 12-months. Results: 319 infants were randomized, 165 to egg and 154 to placebo. Fourteen infants reacted to egg within one week of introduction (despite EW-SPT <2mm at entry) and were unsuitable for intervention. 254 infants (83%) were assessed at 12 months of age. Loss to follow up was similar between groups. Sensitization to EW at 12 months was 20% and 11% in infants randomized to placebo and egg, respectively (OR=0.46, 95%CI 0.22-0.95, p=0.03, Chi-Square test). The absolute risk reduction was 9.8% (95%CI: 8.2% to 18.9%) with a number needed to treat of 11 (95%CI: 6 to 122). IgG4 to egg proteins and IgG4/IgE ratios were higher in those randomized to egg (p<0.0001 for each) at 12 months. There was no effect on the proportion of children with probable egg allergy (placebo 13, egg 8). Conclusions: Introduction of whole-egg powder into the diets of high risk infants reduced sensitization to EW and induced egg-specific IgG4. However 8.5% of infants randomized to egg were not amenable to this primary prevention