Establishing Subclasses of Childhood Eczema, Their Risk Factors and Prognosis

To examine longitudinal eczema subclasses and identify their association with environmental and genetic risk factors and other comorbid allergic outcomes.

This study included 619 participants with a family history of allergic disease participating in an Australian high-risk allergy birth cohort.

Participants were followed throughout 24 time points from birth to 12 years, followed by a subsequent survey at ages 18 and 25 years. Eczema was defined by parental report of persistent skin rash for more than a week in the last 4 weeks with treatment of an eczema medication. Longitudinal latent class analysis was used to determine eczema subclasses. Associations of individual, environmental, and genetic risk factors with eczema subclasses were assessed.

Five subclasses were identified: “early-onset persistent,” “early-onset resolving,” “midonset persistent,” “midonset resolving,” and “minimal eczema.” Early-onset and midonset groups were distinguished by onset of eczema by 6 months and 18 months of age, respectively. Genetic factors such as filaggrin mutations were significantly associated with persistent subclasses. Compared with minimal eczema, participants from both early-onset and midonset persistent classes had increased odds of eczema, allergic rhinitis, and asthma in adulthood; the greatest odds were observed with the early-onset persistent subclass, with odds ratios 9.37 (95% confidence interval [CI] 3.17–27.65), 3.26 (95% CI 1.07–9.93), and 2.91 (95% CI 1.14–7.43) for diagnoses of eczema, allergic rhinitis, and asthma respectively at 25 years old.

Five eczema subclasses were identified based on onset of eczema and persistence. Persistent eczema classes were strongly associated with subsequent allergic diseases in adulthood.

The eczema subclasses identified demonstrated significant differences in early life risk factors and development of subsequent allergic diseases, with earlier persistent eczema associated with the greatest rates of allergic comorbidities. Further study is needed to assess if eczema management strategies can alter the trajectory of the impacts within these subclasses, particularly for persistent eczema.