A pet dog could potentially prevent eczema in at-risk children, study says

Having a pet dog at home could potentially help prevent eczema in children who are genetically predisposed to the condition, according to a new study.

Academics said that having a pet dog in “early life” could have a “protective effect”.

But they stressed that the study did not look at the effect dog exposure could have on existing eczema, and cautioned that introducing a dog could make symptoms worse among some children.

Atopic eczema is a common skin condition that causes itchy skin.

Children with a change in their DNA that increases their chance of developing eczema were less likely to have the condition if they were exposed to a dog in early life (Alamy/PA). PA Media

Researchers said that the condition is caused by a combination of both genetic and environmental factors, but little is known about how the two interact.

An international team of researchers, including academics from the University of Edinburgh, examined data on 280,000 people to investigate whether those who are genetically more likely to develop eczema might respond differently to environmental factors, such as pet ownership, whether they were breastfed or had siblings.

They found that children with a change in their DNA that increases their chance of developing eczema were less likely to have the condition if they were exposed to a dog in early life.

“We detected an observational association between early-life dog exposure and reduction in prevalence of atopic eczema,” the international team of researchers wrote in the journal Allergy.

Researchers performed an initial analysis on more than 25,000 people, which suggested there could be an interaction between seven environmental factors – antibiotic use, cat ownership, dog ownership, breastfeeding, elder sibling, smoking and washing practices – and at least one genetic variant for eczema.

Secondary analysis on data on almost 255,000 people suggested that there was a “nominally significant” link between having a dog in early years, and a variation in genetic code located near a protein involved in immune cell function and inflammation, called interleukin-7 receptor (IL-7R).

Experts said that the findings suggest that the IL-7R protein may provide a potential target for future treatment or prevention of eczema.

Professor Sara Brown, from the University of Edinburgh’s Institute of Genetics and Cancer, said: “The most difficult questions I’m asked by parents in clinic are about why their child has eczema, and how they can help.

“We know that genetic make-up affects a child’s risk of developing eczema, and previous studies have shown that owning a pet dog may be protective, but this is the first study to show how this may occur at a molecular level.

“More work is needed, but our findings mean we have a chance to intervene in the rise of allergic disease, to protect future generations.”

Dr Marie Standl, from Helmholtz Munich, said “This study sheds light on why some children develop eczema in response to environmental exposures while others don’t.

“Not every preventive measure works for everyone, and that’s precisely why gene-environment studies are crucial.

“They help us move toward more personalised, effective prevention strategies.”