Early Egg Introduction Does Not Lower Allergy Risk

Regular egg consumption starting at 4 to 6 months of age does not change the risk for egg allergy at 1 year of age or older, compared with delayed introduction of eggs, the authors of a new study report.

However, some of the findings, which come from the Starting Time of Egg Protein (STEP) randomized, double-blind trial, do hint at a possible benefit of early egg introduction, they point out.

STEP participants had no allergic symptoms at the time of enrollment, although they had a hereditary risk for allergies, Debra J. Palmer, PhD, from the School of Paediatrics and Child Health, The University of Western Australia in Crawley, and colleagues write. This distinguishes STEP from studies such as the Learning Early About Peanut Allergy (LEAP) trial, for which an existing allergic disease, such as eczema, was a prerequisite. In LEAP, early and sustained consumption of peanut products was associated with a significant decrease in the incidence of peanut allergy.

“We found no evidence that regular egg intake from 4 to 6.5 months of age substantially alters the risk of egg allergy by 1 year of age, in infants who are at hereditary risk of allergic disease and had no eczema symptoms at study entry,” the authors conclude. “There is no need for routine testing of infants without eczema in the community to determine egg sensitization status prior to the introduction of egg and egg-containing foods when solids are introduced.”

The study was published online August 21 in the Journal of Allergy and Clinical Immunology.

Children were enrolled in STEP between the ages of 4 and 6.5 months. Their mothers had atopy, but the children themselves had no eczema or allergic illness and no previous consumption of egg. They were randomly assigned to receive an intervention (egg) or control (no egg) powder that was mixed into their food. The two preparations were similar in color, smell, texture, and taste and were administered once a day from the time of randomization until the children were 10 months of age. At 10 months of age, parents introduced cooked egg into the diets of all children in both trial groups.

Of the 820 original participants, 748 had the skin prick test and egg challenge at the 12-month examination. IgE-mediated egg allergy was diagnosed in 26 of 371 (7%) children in the intervention group and 39 of 377 (10.3%) in the control group.

The relative risk, adjusted for city, infant sex, breast-feeding status, and paternal history of allergic disease (aRR), was 0.75 (95% confidence interval [CI], 0.48 – 1.17; adjusted P = .20). But while “the sample size was sufficient to rule out large increases in egg allergy risk…we cannot rule out potentially important benefits,” the authors write.

Sensitization to egg was observed in 10.8% of the children in the egg group vs 15.1% of the controls (aRR, 0.77; 95% CI, 0.54 – 1.10; P = .15). Between randomization and 1 year of age, eczema occurred in 10.7% of the children in the egg group and 11.9% of the controls (aRR, 0.84; 95% CI, 0.57 – 1.23; P = .37).

Two infants in the egg group and one in the control group developed anaphylaxis in response to the raw egg challenge at 12 months. However, there were no anaphylactic responses to the egg powder used in the study. In addition, of all 65 infants in either group who had an allergic response to raw egg challenges, 60 were consuming baked or cooked eggs with no problems. “This highlights a key public health message: that egg introduction at 4-6.5 months of age for infants without eczema is safe to do so at home without the need for prior egg sensitization testing.”

In a per-protocol analysis, 9 of 305 infants in the egg group (3%) and 31 of 312 infants in the control group (9.9%) had IgE-mediated egg allergy at 12 months of age (aRR, 0.32; 95% CI, 0.16 – 0.65; P = .002). However, more children in the egg group than the control group were excluded from the per-protocol analysis because of a perceived adverse reaction (P = .02) or a confirmed allergic reaction (P = .0004) to the study powder.

The authors note that the small difference in the timing of introduction between the two groups (4 to 6 months vs 10 months) may have been too short to show a contrast in allergic response. In the LEAP trial, peanuts were introduced to the intervention group at 4 to 11 months of age, compared with 5 years of age for the control group. However, the researchers note they were trying to reproduce the common practice of introducing eggs at about 10 months of age. Also, an earlier study showed that waiting until after 10 months of age was associated with a higher risk for egg allergy.

The authors have disclosed no relevant financial relationships.