Can You Be Allergic to Your City?

Scranton, Pennsylvania. It's a charming town in upstate Pennsylvania with a history steeped in the Western Railroad and the steam engine. Just know if you plan on moving there, you might want to stock up on tissues and allergy medication because, according to the Asthma and Allergy Foundation of America's 2021 Allergy Capitals report, Scranton is the worst city to live in the U.S. if you have seasonal allergies. The foundation's annual rankings seem to underscore that yes, you can be allergic to a city.

An estimated 50 million Americans have nasal allergies, the sixth-leading cause of chronic illness in the United States. And no wonder. According to researchers, living in the United States may raise the risk of your getting some allergies. In fact, children born in the United State have a 33 percent chance of having an allergy, while children born in other countries have a one in five chance.

But if you move from one U.S. city to the next, can new allergies flare up that you never had before? "There are different (allergen) patterns in different parts of the country," Dr. Stephen Tilles, a Seattle allergist and president of the American College of Allergy, Asthma, & Immunology said when we originally spoke to him in 2017. "It's a huge issue."

Part of the reason is that different allergens are unique to specific areas. In Boston, for example, Tilles says, ragweed and grass are common allergens, and therefore people are exposed and sensitized to them. If a person were to move from Boston to, say, Seattle where there is no ragweed but lots of alder trees, then that person may develop an allergy to alder pollen.

That's because allergies are abnormal reactions by the body's immune system to foreign substances — allergens. Every second of every day, the body's immune system battles hostile invaders, including microorganisms such as bacteria and viruses. Like in all wars, mistakes are made. Sometimes the immune system will incorrectly assume that a harmless substance, such as ragweed pollen, is out to do harm.

The body responds by creating a special antibody called immunoglobulin E (IgE). The antibodies combine with mast cells in the skin, nose, throat and lungs to release a squad of Stormtroopers named histamines and leukotrienes. These biological commandos attack the allergen. As they do, it causes an allergic response — sneezing, watery eyes, itching, rash, runny nose and other classic reactions. 

Allergies also have a genetic and environmental component to them. Some people are predisposed to allergies because their parents have them. However, the timing of when people start developing symptoms is based on environmental exposure. Once a person passes a certain level of exposure to an allergen, then the sneezes start.

But it's not just a new location that can prompt new allergies. If winter months are mild in many areas, an increasing number of people will develop springtime allergies even though they have never had them before. In fact, experts say, many adults are developing seasonal allergies later in life because of climate change. Rising temperatures extend the period during which plants release pollen. As a result, the allergy seasons are longer and more intense. The increase is also being fueled by the rise of carbon dioxide in the atmosphere. The situation has gotten so dire that researchers say pollen counts will more than double by 2040. 

So, is there a place that you can move to where allergies are not a problem? In the mid-1900s, doctors used to send people to Arizona. In recent decades, however, the population of the state has grown. As the population expanded, so did home building. "People started planting grass," Tilles says. And, well, with grasses come allergies.

If not Arizona, then perhaps Alaska? "There are many gainfully employed allergists in Alaska," Tilles jokes.