Early life atopic dermatitis increases food allergy risk throughout childhood

Food allergy (FA) is often co-expressed with atopic dermatitis (AD), particularly early in life. However, how early life atopic dermatitis affects food allergy risk and phenotype are not well described. Two-hundred-eighty-five high-risk infants were enrolled before birth in the Childhood Origins of ASThma (COAST) birth cohort and followed prospectively for 17 years. Details regarding atopic dermatitis and food allergy were obtained through yearly questionnaires and reports of physician diagnoses. Latent class analyses were performed and AD phenotype was assessed in relation to food allergy risk. Fisher’s exact test was used for comparisons among groups. At age 1, children with AD were more likely to have FA (5% vs 21%, p=0.003), and this increased FA risk persisted throughout childhood. Latent class analyses revealed three distinct phenotypes of AD: healthy/transient AD, late onset AD, and early/recurrent AD. Children with early/recurrent AD were most likely to have food allergy at age 1 (5.3% in healthy/transient AD, 3.4% late-onset AD, 21.9% early/recurrent AD, p=0.0004 healthy vs early/recurrent) and throughout childhood. In contrast, children with onset of AD at age 3 or later (late-onset phenotype) were not more likely to develop food allergy compared to healthy children at any age. AD at age 1 increases food allergy risk throughout childhood. This effect is most pronounced in children with persistent AD, while children with late-onset AD are not affected. These data suggest that immunologic changes in AD, which occur early in life, influence food allergy risk throughout childhood.