Why Do We Get Allergies?

Allergies can be a nightmare. Regardless of age, gender, or background, everyone is susceptible to developing an allergy. Allergy symptoms can range from coughing, wheezing, and watery eyes, to more potentially dangerous outcomes, such as anaphylaxis.

Our immune system is critical to our health, providing us with protection from illness. However, an allergic reaction is essentially a heightened immune system response that is prompted by exposure to a particular substance. This exposure can occur through ingestion, inhalation, or direct skin contact. Such substances a person may be affected by include pollen, mold, pet dander, or certain food items. When the body creates antigens against these irritants, it results in an allergy.

Why is it that some of us live our whole lives allergy-free while others deal with allergies on a regular basis? While scientists can't say for sure, it's believed that genetics and environmental factors likely have something to do with it.

The odds of developing allergies at some point during your life are higher if an immediate family member also has an allergy. For instance, the Carolina Asthma & Allergy Center reports that a child has a 30% to 50% chance of developing allergies if a parent also experiences allergies. If both of your parents do, then the odds nearly double to anywhere between 60% and 80%. For most people, signs of an allergy tend to emerge during early childhood, but others may find themselves affected by allergies as they age.

In these cases, a person may have unknowingly been prone to allergies their whole life but only became aware of it when exposed to the allergen for the first time later in life. This may include getting a pet or trying a new product containing fragrance. Alternatively, some experts theorize that cleanliness may play a role in one's risk of developing allergies. Deemed the "hygiene hypothesis," the concept suggests that those who regularly utilize antimicrobial products to reduce germ exposure may be more susceptible to allergies.

Some research suggests that where a person lives may also influence their risk of developing allergies. In a 2017 study published in the scientific journal Thorax, researchers examined approximately 10,200 people between the ages of 26 to 54 from around the world. Between farm environments, rural locations, and inner-city settings, the study team looked to see which environments produced greater allergy protection in participants who lived in these locations up until the age of 5. The research findings suggested that living on a farm during early childhood was linked with greater protection against the development of allergies and other respiratory problems in adulthood. The researchers indicated that farm environments may offer a greater degree of germ and allergen exposure compared to alternate environments. As a result, they subsequently decrease one's sensitivity to these substances. 

Similar findings were found in a 2019 study published in the Annals of Allergy, Asthma, and Immunology. Survey data from more than 25,000 women in Iowa between the ages of 55 and 69 revealed that participants who resided in farm, rural, or small urban environments had a lower risk of adult allergies than those living in big cities with populations upwards of 10,000 people.