Early respiratory infection burden linked to atopic dermatitis

Respiratory infections in early childhood are a risk factor for atopic dermatitis (AD), and the higher the number of infections, the greater the risk, as shown in a study.

Researchers used data from the 2010 Danish Copenhagen Prospective Studies on Asthma in Childhood (COPSAC2010) birth cohort, wherein children aged 0–10 years were monitored for infection diagnoses, AD diagnosis, Scoring Atopic Dermatitis (SCORAD) index score, systemic antibiotics, and filaggrin gene (FLG) status. They also included a second birth cohort from the US Vitamin D Antenatal Asthma Reduction Trial (VDAART) to validate their findings.

The COPSAC2010 cohort included 663 children, while the VDAART cohort included 707 children. The risk of AD during age 0–10 years was assessed using diagnostic criteria in COPSAC2010. Parental report of physician AD diagnosis until age 6 years was used in VDAART.

In COPSAC2010, children in the top tertile of infection burden (n=221, 51 percent male) had around 60-percent greater odds of yearly AD prevalence during ages 0–10 years compared with those in the third tertile (n=221, 49 percent male) (infection episodes: adjusted odds ratio [AOR], 1.61, 95 percent CI, 1.05-2.47; p=0.03; infection days: AOR, 1.69, 95 percent CI, 1.11–2.58; p=0.01).

Each infection episode was associated with higher odds of AD, regardless of systemic antibiotic treatments and FLG variants. Associations were primarily driven by respiratory infections.

In VDAART, children in the top (n=235, 53 percent male) vs third (n=236, 50 percent male) tertile of infection episodes had greater odds of AD at ages 0–6 years (OR, 1.76, 95 percent CI, 1.16–2.70; p=0.01), with the odds increasing by 3 percent with each infection episode (OR, 1.03, 95 percent CI, 1.01–1.05; p=0.002).