Maternal consumption of peanut during pregnancy is associated with peanut sensitization in atopic infants.

BACKGROUND Peanut allergy is typically severe, lifelong, and prevalent. OBJECTIVE To identify factors associated with peanut sensitization. METHODS We evaluated 503 infants 3 to 15 months of age (mean, 9.4 months) with likely milk or egg allergy but no previous diagnosis of peanut allergy. A total of 308 had experienced an immediate allergic reaction to cow's milk and/or egg, and 204 had moderate to severe atopic dermatitis and a positive allergy test to milk and/or egg. A peanut IgE level ≥5 kU(A)/L was considered likely indicative of peanut allergy. RESULTS A total of 140 (27.8%) infants had peanut IgE levels ≥5 kU(A)/L. Multivariate analysis including clinical, laboratory, and demographic variables showed frequent peanut consumption during pregnancy (odds ratio, 2.9; 95% CI, 1.7-4.9; P < .001), IgE levels to milk (P = .001) and egg (P < .001), male sex (P = .02), and nonwhite race (P = .02) to be the primary factors associated with peanut IgE ≥5 kUA/L. Frequency of peanut consumption during pregnancy and breast-feeding showed a dose-response association with peanut IgE ≥5 kU(A)/L, but only consumption during pregnancy was a significant predictor. Among 71 infants never breast-fed, frequent consumption of peanut during pregnancy was strongly associated with peanut IgE ≥5 kU(A)/L (odds ratio, 4.99, 95% CI, 1.69-14.74; P < .004). CONCLUSION In this cohort of infants with likely milk or egg allergy, maternal ingestion of peanut during pregnancy was strongly associated with a high level of peanut sensitization.