London - Dogs that live an "urban lifestyle" in city flats with single people and no other pets are nearly twice as likely to develop allergies, researchers say.
A study of 169 pets led by the University of Helsinki found that they are more likely to have food intolerances or eczema.
A lack of other animals or family members means the canines may have fewer of the bugs on their skin that are vital for keeping their immune system healthy, the research found.
Dr Jenni Lehtimaki, of the university’s faculty of biological and environmental sciences, said: "On the other hand, dogs living in rural areas with a large family and regular contact with other animals were least likely to have allergic disease."
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The dog study, published in the journal PNAS, states that the team’s results are "likely to apply also to humans".