Eczema in early childhood increases the risk of allergic multimorbidity.

Background: Eczema in early childhood is associated with the development of subsequent allergic diseases, including food allergy (FA), asthma and hay fever. However, eczema has a heterogenous presentation regarding onset age and persistence, which may lead to different allergic outcomes during childhood/adolescence. Recently, sub-phenotypes of eczema have been suggested as predictors of allergic multimorbidity. Thus, we aimed to identify associations of eczema phenotypes with FA, asthma and hay fever during childhood/adolescence. Additionally, we described the trajectories of eczema, asthma and hay fever stratified by FA presence.

Methods: TRACKER (Trajectories of Allergy in Children in Real Life Databases) is a population-based cohort study of 6852 children/adolescents from the Lifelines cohort. We investigated the associations of seven eczema phenotypes, based on onset age and persistence, with FA, asthma and hay fever using logistic regression, adjusted for appropriate covariates. Disease trajectories were determined by calculating prevalence at different ages.

Results: Participants who suffered from eczema throughout childhood showed higher risks of developing FA, hay fever and asthma. "Very early onset-persistent" eczema showed the strongest associations with FA, asthma and hay fever. The prevalence of eczema, asthma and hay fever at all ages was significantly higher in participants with FA, compared to those without.

Conclusion: One of the largest cohort studies on this topic to date shows that (very) early onset and persistent eczema increases the risk of allergic multimorbidity. Identification of infants at risk for developing (very) early onset eczema is of utmost importance to prevent allergic multimorbidity.