Spring breezes carry tree pollens first, said microbiologist Frances Coates of Ottawa, who identifies pollen and spores to assess allergen levels collected from 30 stations across Canada at Aerobiology Research Laboratories.
"If someone has allergies to more than one tree, say ash and birch, which is not that uncommon to have allergies to those two trees, they're showing up together," said Coates. "So people are getting a double-whammy from their allergies."
Hot weather generally creates a shorter tree pollen season with higher counts, meaning people with those allergies don't get sick for as long, she said.
"I hear that every year that everybody says it's the worst season," said Coates.
After 20 years of collecting data, Coates see no clear overall patterns, because every tree species reacts differently to weather conditions each year.
Allergist Dr. Jason Lee in Toronto also hears patients say it's getting worse.
"It's actually not necessarily the case," Lee said. "Most allergen pollen levels are determined by the number of trees and grasses out there and those levels don't fluctuate that much in total."
Rather, when people develop symptoms and how severe they perceive them varies from year to year because of factors like sinus infections, Lee said.
Dr. Karen Binkley, an allergist and clinical immunologist at the University of Toronto wrote a guide for patients with allergies and asthma.
Lee and Binkley both recommend non-medical approaches first for everyone coping with allergies as well as treatments:
- Keep doors and windows closed to keep out pollen.
- Wear wraparound sunglasses when outside.
- Use a salt water rinse for excess mucous and pollen.
- Use nasal strips at night if congestion is a problem.
- Over-the-counter medications like antihistamines, nasal sprays or eye drops.
- Allergy injections.
- Under-the-tongue tablets for grass allergies.
"When everything else doesn't work, there are allergy injections," Binkley said in an interview on Wednesday.
"They don't work for everybody and they can take up a long time to work, so we usually sort of keep those in reserve for when other things fail."
Allergy patients have to go to a doctor for the weekly allergy shots, which carry a slight risk of anaphylaxis and a 1 in 2.5 million risk of death, Lee said.
Kirsten Cornelson just got her first allergy shot from Lee.
"Runny nose, itchy eyes, my breathing isn't as good because I have asthma," Cornelson said.
Previously, she took over-the-counter medications but didn't like the sedating side-effect.
A newer option for grass allergies is a daily pill taken under the tongue to desensitize the immune system to grass pollen.
"Essentially you are slowly escalating the amount of grass pollen you can be exposed to and that seems to induce an immune response," Lee said.
So far, the tablets seem to help for at least one season but they aren't quite as effective as the shots, Binkley said.
A vaccine for grass allergies is also being tested in a clinical trial.
Prof. Mark Larché of McMaster University in Hamilton said those injections could offer the same benefits as allergy shots over a shorter course with fewer side-effects.