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Gene–Environment Interaction Affects Risk of Eczema

Written by Prof Sara Brown and Dr Lauren Kelly

Having a pet dog in the family home could help protect a child from developing eczema, especially if they are genetically predisposed to this condition. Using population research to study 300,000 people, and detailed studies on skin cells in the lab, we have shown molecular signals from dog allergen can dampen down inflammation in human cells.

Eczema is an itchy skin disorder caused by a combination of genetic make-up (your DNA) and environmental effects. We do not know which environmental effects are important, but previous research has shown that having pets or living with siblings may play a role. Taking antibiotics, being breast- or bottle-fed, exposure to cigarette smoke and different ways of washing may also be important.

Our study aimed to investigate whether people who are prone to developing eczema might respond differently to environmental effects. We gathered information from large population studies across the UK, Europe and Australia. Focusing on genetic changes that are already known to increase eczema risk, we used statistical tests for interaction with selected environmental factors in a total of 25,000 people. We repeated tests that showed possible interactions using data from a further 280,000 people.

One result stood out in these analyses – a region of DNA code that increases the risk of eczema overall, but in children or babies whose families owned a pet dog, that risk disappeared. Hence dog exposure appears to be protective in people who are genetically predisposed to eczema.

To understand this further, we tested skin cells in the laboratory for their response to dog allergen. Results showed evidence that skin cells react through a signal receptor called IL-7R.

Our results are exciting because they show for the first time a gene-environment interaction mechanism to explain the protective effect of having a pet dog. Further work is needed before this can be used to prevent or treat eczema in the future.

The full paper is available to read online and we are grateful to the many funders who supported different aspects of this work, detailed here: https://doi.org/10.1111/all.16605.

Related publication:
Gene–Environment Interaction Affects Risk of Atopic Eczema: Population and In Vitro Studies
Standl M, Budu-Aggrey A, Johnston LJ, et al.
Allergy, 2025; 0:1–12
doi: 10.1111/all.16605

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