This article was originally published in The Queen’s Journal
Colorful flowers and delicate blooms on the trees aren’t the only sign that spring is truly coming. For many, allergies are a sign of the changing seasons. As many as one in four Canadians suffers from allergic rhinitis and its symptoms – runny nose, sneezing, itchy/tearing eyes, and sometimes coughing. With climate change, the problem may be more acute: Experts believe that increased greenhouse concentrations in the atmosphere and higher temperatures are causing plants’ flowering seasons to lengthen, leading to more pollen in the air. Also, seasonal allergies tend to be exacerbated by air pollutants such as diesel exhaust particles.
Ann Ellis, chair of the Queen’s Department of Allergy and Immunology and clinical scientist at Kingston Health Sciences Center (KHSC), pays close attention to how seasonal allergies have changed in the past decade. It has some troubling news: It’s still hard to distinguish between patterns and make firm predictions.
“Every year is different,” she says. “This year’s tree pollen season started already on time compared to 10 years ago, but in the recent past we’ve had a very late start to tree pollen season, due to much longer winters.”
While 2021 saw record levels of birch pollen, 2022 was by far the most common year in total for southern Ontario. But in April, warmer days followed by cold nights and even snow bring the pollination to a halt.
“Expect the unexpected when it comes to allergies,” is Dr. Ellis’ main advice for those looking to take an antihistamine every spring.
But Dr. Ellis believes that shorter spring and fall — with longer winter and summer — make a big difference, at least in how people perceive their allergy symptoms.
“We end up with longer winters and more time to forget how bad our seasonal allergies are, so they affect us more when they come back,” she says.
North America also experiences hotter summers with higher humidity, which can be challenging for people with asthma. Because humidity fuels dust mite growth, staying indoors doesn’t always provide comfort—at least if the person doesn’t have an air conditioner or dehumidifier.
Some practical advice
Dr. Ellis recommends that people with seasonal allergies keep their windows closed and turn on the air conditioner when possible, and avoid hanging clothes on clotheslines outside to prevent pollen from being picked up. Rinsing the nose with saline may also help.
At local drugstores, people can look for non-sedating second-generation antihistamines like cetirizine or loratadine — Dr. Ellis says it’s best to avoid the old, sedating antihistamines that may have unintended side effects and are not as effective as the newer drugs. If over-the-counter medications are enough to provide relief, she suggests seeing a doctor for prescription medications like new antihistamines and intranasal corticosteroids, which reduce swelling and mucus in the nose.
In the event that these tips do not solve the problem, seeing a specialist may be the best option.
“Ask your doctor for a referral to an allergist for a skin examination and to find out what you are specifically allergic to,” Dr. Ellis advises. “An allergist can offer personalized immunotherapy options based on these findings that actually treat the underlying allergy, rather than just masking the symptoms.”
From a public health perspective, Dr. Ellis says urban planning can make a difference, for example, in planting female trees that don’t pollinate — while they drop nuts and fruits, which can be messy, they don’t cause an increase in pollen count.
Dr. Ellis leads the Kingston Environmental Exposure Unit at KHSC. At this facility, she and her team enjoy a precisely controlled environment that allows them to study the impact of allergens on health at any time of the year.
“The highly controlled indoor environment eliminates the variables of the weather, the environment of the participants, and the changing characteristics of seasonal allergens,” explains Dr. Ellis. “The computer-controlled delivery system and strict monitoring ensures that allergen levels maintained in the unit remain within specified requirements.”
Since the 1980s, the unit has been used to advance our knowledge of the effectiveness of various anti-allergic treatments, including antihistamines, nasal corticosteroids, and other medications.