Do pets protect children from developing asthma?
In this entry, I would like to address the issue of pet ownership and asthma. Pets, especially cats and dogs, are important members of many households. While it is well known that many people are allergic to cats and dogs, whether being exposed to them at a young age can cause asthma is less clear.
Allergies and asthma are closely related, especially in children. Many individuals with allergic asthma are allergic to cats and/or dogs. When they come in contact with these pets, either directly or even going into a house where dogs or cats are present, they can develop symptoms of hay fever (sneezing, itchy eyes, runny nose) and/or asthma (wheeze, cough, and shortness of breath).
In fact, many people may discover later in life that they are allergic to certain pets after having unexplained worsening of their asthma as a house guest, only to make the connection after the fact that the reason for worsening asthma was being in a house where there was a cat or dog. (This was my experience with my cat allergy.) This situation applies to individuals who have developed allergic sensitization to pets, and for whom these exposures are asthma triggers. But what about the risk of pet ownership on developing this sensitization to pets and occurrence of wheeze? This is an important question for individuals considering having a pet in the home, especially with young children around.
Pet exposure and the development of asthma
While it would seem logical that exposure to pets at a young age would promote the development of allergies or asthma, in fact, there may be a protective effect of owning pets on the development of asthma in young children. The reason is that pets in the house not only shed dander, but also certain natural biologic products, such as endotoxin, which may be protect against developing allergies and asthma.
Several recent research studies have looked specifically at the association between pet exposure and development of asthma or wheeze. For example, there seems to be a difference between exposure to dogs through ownership in the home and casual exposure, such as when visiting a house where there is a dog. One study found that there was a protective effect of dog ownership on the development of allergies to pollens (not dogs); this was not found in children of similar age who had casual exposure to dogs. There have been similar studies looking at childhood exposure to cats, which have found that avoiding cat exposure does not necessarily protect them from developing cat allergy. In some cases, especially with high level exposure to cat allergens, there is a protective effect with respect to becoming allergic to cat and later developing asthma.
Many people express legitimate concerns about getting a pet for young children in their home. These concerns are especially relevant when one or both parents have asthma and allergies, as we have discussed that there are inherited factors in allergies and asthma. While it makes no sense to get a pet to which parents are known to be allergic, there is by no means any guarantee that a child of allergic parents are at high risk of becoming allergic to pets or other things. And there are many intangible benefits to pet ownership for children and adults alike. Whether to get a pet or not should be discussed directly with your doctor, pediatrician, or allergist. Being ‘allergic' doesn't necessarily mean that your family may not be able to enjoy the company of pets in the home.