A study published in Nature Communications found that owners and pets who live in a more urban environment were more likely to exhibit allergic symptoms. The reason? Both people and dogs in urban communities are limited in their exposure to healthy microbes that exist in a more rural or wilderness-type environment.
Interestingly, the increased ‘risk’ of allergies in an urban environment is largely attributed to lack of protective-effects. The protective effects include less exposure to livestock, western diets (e.g. American diet) and small family size. In other words, households with a lesser number of children, or no children and only 1 pet have a higher risk of allergies. According to another study, pet dogs have a reduced risk of allergies when exposed frequently to other animals as well as when living in a larger family.