A new study has revealed insights into how a child’s environment interacts with their genes to influence the risk of developing atopic eczema – a chronic skin condition marked by dryness, itching, and inflammation (Figure 1). While genetics are known to play a key role, researchers have now shown that early-life exposures, including pet ownership, may alter how these genetic risks manifest.
Figure 1: Graphical abstract.
The study draws on data from several research cohorts and identifies interactions between common eczema-related genetic variants and early-life environmental exposures. These findings could help explain why some children with a genetic predisposition develop eczema, while others remain unaffected.
Researchers examined 24 well-established genetic variants associated with eczema and assessed their potential interactions with 18 early-life environmental factors, including pet ownership, antibiotic use, breastfeeding, household smoking, and bathing habits.
Seven environmental factors showed evidence of interaction with at least one genetic risk variant, with 14 significant gene-environment interactions identified in total. Notably, dog ownership stood out.
In the larger dataset, one of the most compelling findings was the interaction between dog exposure and a specific genetic variant located on chromosome 5, near the IL7R gene. This gene encodes the interleukin-7 receptor, a molecule involved in regulating immune cell development and activity.
Laboratory tests using human skin cells revealed that this genetic variant affects how much interleukin-7 receptor is expressed in the skin. Interestingly, exposure to dogs appeared to modify this effect-dampening the genetic signal and thereby reducing skin inflammation associated with eczema. In essence, dog ownership seemed to provide a protective effect, particularly in children with this genetic susceptibility.
While more research is needed to fully understand the biological mechanisms involved, these results offer an important step toward untangling the complex web of genetic and environmental influences on eczema.
The study highlights the potential of early-life interventions to prevent allergic diseases and highlights the value of studying gene-environment interactions on a population scale. With further exploration, such insights could lead to personalized prevention strategies that protect children from developing eczema and other allergic conditions.
Journal article: Standl, M., et al. 2025. Gene–Environment Interaction Affects Risk of Atopic Eczema: Population and In Vitro Studies. Allergy.
Summary by Stefan Botha
