Respiratory Infections During Early Childhood Linked to Higher Risk of Atopic Dermatitis: JAMA
Denmark: A large study involving two independent birth cohorts found that a higher burden of respiratory infections during early childhood was associated with an increased, dose-dependent risk of developing atopic dermatitis (AD). The findings suggest a long-term link between early respiratory infections and AD, providing stronger evidence for an association that had previously been inconsistent.
The study, published in JAMA Dermatology, was led by Nicklas Brustad from the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC), Herlev and Gentofte Hospital, University of Copenhagen, Denmark, and colleagues.
Atopic dermatitis is one of the most common chronic inflammatory skin disorders in children, and environmental exposures during early life have been proposed to influence its development. While previous research has suggested a possible relationship between childhood infections and AD, findings have been inconsistent. To clarify this association, researchers examined whether the overall burden of early-life infections, as well as specific infection types, was linked to the risk of developing AD during childhood.
The investigators analyzed data from two independent birth cohorts: the Danish COPSAC2010 cohort and the US Vitamin D Antenatal Asthma Reduction Trial (VDAART). The COPSAC2010 cohort included 663 children followed from birth to 10 years of age, while the VDAART cohort comprised 707 children monitored until 6 years of age. Data analysis was performed between January and February 2026.
In the Danish cohort, parents recorded daily episodes of common childhood illnesses, including colds, acute otitis media, tonsillitis, pneumonia, gastroenteritis, and fever during the first three years of life. Researchers also collected information on atopic dermatitis diagnoses, disease severity using the Scoring Atopic Dermatitis (SCORAD) index, systemic antibiotic use, and filaggrin (FLG) gene variants. The findings were then validated using similar infection and physician-reported AD data from the US cohort.
Key findings from the study include:
- Children with the highest burden of infections during the first three years of life had a significantly greater risk of developing atopic dermatitis than those with the lowest infection burden.
- Each additional infection episode was associated with a progressive increase in the risk of AD, demonstrating a dose-dependent relationship.
- Respiratory infections, rather than non-respiratory infections, accounted for most of the observed association with AD.
- The relationship between infection burden and AD remained significant after adjusting for systemic antibiotic use and filaggrin (FLG) gene variants.
- The findings were independently replicated in the US VDAART birth cohort, strengthening the consistency of the results across two populations.
The researchers concluded that a higher burden of early-life respiratory infections is associated with a dose-dependent increase in the risk of childhood atopic dermatitis. The consistent findings across two independent birth cohorts strengthen evidence for a long-term association, although further studies are needed to clarify the underlying biological mechanisms and their implications for disease prevention.
Reference:
Brustad N, Wang T, Sultan T, et al. Early Respiratory Infection Burden and Atopic Dermatitis in Childhood. JAMA Dermatol. Published online July 29, 2026. doi:10.1001/jamadermatol.2026.2626
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