Episode Transcript
Even if cats and dogs make you sneeze, will you save your kids from aggravating allergies by getting them a pet?
Early pet exposure reducing the risk of allergies in children—it's part of something called the hygiene hypothesis, and it's been tossed around for a few years now. Evidence is mounting that it may be true. Studies found that exposure to pets in early years of a child's life might significantly lower the risk according to some pediatric allergy specialists.
The Hygiene Hypothesis: Early Pet Exposure and Allergy Risk
The allergy researchers followed a group of about 500 children almost equally split between boys and girls from birth to age seven. Children were checked regularly with blood tests to measure antibodies that cause allergies, skin reaction tests that show if someone is sensitive to an allergy, and a breathing test to measure their lung function commonly used to detect if their child has an asthma flare or not.
The researchers also collected information on exposure to cigarette smoke, home and daycare environments and measured allergen levels in the household such as dust and other air samples. They also asked about pets in the home.
How Pets Impact Allergy Risk in Children
So the allergists found that children who lived with two or more animals were significantly less likely to have a positive skin test, which signifies a reaction to the allergen rather than those who had no exposure to pets. Children with pets were also less likely to have allergen antibodies in their blood. Boys especially seem to benefit from pet exposure. Not only did they have lower antibody levels, they had better lung tests and less evidence of asthma if there were two or more cats or dogs in the house.
Cleanliness vs. Allergies
The study adds to the growing literature about the hygiene hypothesis that the cleaner we live, which is common in our Western world lifestyle, the more likely we'll get asthma and allergies. It confirms the observation that children with a history of pet exposure in the first years of life may have less asthma. Boys do tend to get more asthma and allergies, though.
The study falls short of proving that pets can prevent allergies and asthma. You shouldn't automatically just go out and get two dogs and two cats. It's a correlation that may be true but it hasn't been proven yet. It could be that the study shows that only children who have a risk of allergy or asthma tend not to have cats or dogs in the house.
Potential Factors Beyond Pet Exposure
By working on this same hygiene hypothesis, pets may not even be a necessary factor in increasing a child's immunity. Siblings might also play the same role as pets. Infections in early life, especially with viruses, may help drive the immune system away from being sensitive and causing allergies. Kids can get the same kind of exposure from older siblings in the first month of a child's life. Usually, the older siblings will bring home lovely viruses from school, or the children themselves will be exposed to viruses at daycare.
Just like we say don't go out and get two dogs or two cats just to keep your kids from getting allergies, we don't necessarily mean you have to put them in daycare in order to expose them to these viruses. More studies need to be done following children in their early lives before any conclusions can be made about the hygiene hypothesis.
Balancing Pet Ownership and Allergy Risks
So does this mean you should go out and get a pet? Well, not so fast. If there's someone in the house who has an allergy to a dog or cat, you really don't want to put that family member through misery. Also, genetics plays a large role as well. Children have a one in three chance of developing allergies if just one of their parents has allergies. If both of their parents have allergies, their risk is nearly 70%. The risks increase by similar amounts for asthma. Pets are a lot of responsibility, too. Be sure to think about all family members, pets included, if considering a dog or cat.
updated: March 4, 2024
originally published: September 14, 2015