RESUMO
BACKGROUND: Epidemiologic evidence suggests delayed introduction of egg might not protect against egg allergy in infants at risk of allergic disease. OBJECTIVE: We sought to assess whether dietary introduction of egg between 4 and 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 1 first-degree relative with allergic disease. Infants with a skin prick test (SPT) response to egg white (EW) of less than 2 mm 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 an EW SPT response of 3 mm or greater at age 12 months. RESULTS: Three hundred nineteen infants were randomized: 165 to egg and 154 to placebo. Fourteen infants reacted to egg within 1 week of introduction (despite an EW SPT response <2 mm at entry) and were unsuitable for intervention. Two hundred fifty-four (83%) infants 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 (odds ratio, 0.46; 95% CI, 0.22-0.95; P = .03, χ2 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, 6-122). Levels of IgG4 to egg proteins and IgG4/IgE ratios were higher in those randomized to egg (P < .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 levels. However, 8.5% of infants randomized to egg were not amenable to this primary prevention.
