- Design
- Two prospective birth cohorts (COPSAC2010 and VDAART)
- Population
- 663 Danish and 707 US children followed from birth
- Primary outcome
- Atopic dermatitis to age 10 (Denmark) or 6 (US)
- Effect
- Top vs bottom infection tertile: aOR 1.61 (1.05–2.47) Denmark; OR 1.76 (1.16–2.70) US
Two independent birth cohorts were analysed. In the Danish COPSAC2010 cohort, 663 children had infections logged in daily diaries until age 3 and were assessed for atopic dermatitis to age 10; in the US VDAART cohort, 707 children had parent-reported infections and physician-diagnosed eczema to age 6.
In Denmark, children in the highest third of infection episodes had higher odds of eczema across childhood than those in the lowest third (adjusted OR 1.61, 95% CI 1.05 to 2.47), independent of antibiotic courses and filaggrin variants. The association was driven mainly by respiratory infections. The US cohort showed the same pattern (OR 1.76, 1.16 to 2.70), with odds rising by about 3% per episode.
This is an association. It could reflect a shared immune predisposition rather than infections causing eczema. It is useful in counselling — parents often ask why a child's skin flares after a run of colds — but it is not a reason to change infection management.
- Expect eczema flares after respiratory infections in young children, and plan emollient and steroid use accordingly.
- Tell parents that frequent early colds and eczema often travel together.
- Do not withhold antibiotics that are needed — the association was independent of antibiotic use.
- Keep filaggrin status and family atopy in mind as separate risk factors.
Why it matters
It gives a consistent answer, in two cohorts, to a question earlier studies left unclear.
Don't overread it
An association across two cohorts — it does not show that preventing infections would prevent eczema.
The statistics, in plain English
An adjusted odds ratio of 1.61 means children with the most infections had about 60% higher odds of eczema. The lower limit of 1.05 is close to 1.0, so the effect could be small. Replication in a second, separate cohort makes chance a less likely explanation.
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