As spring approaches and warmer weather arrives, pollen and fungal spore experts are saying a prolonged period of colder weather has suppressed early allergen activity.

Aerobiology Research Laboratories – based in Ottawa – is forecasting what they say is a "significant" surge in pollen levels this weekend (Feb. 28) and in the weeks ahead in Victoria and Vancouver.

"We've observed unusually low counts of alder, hazel, elm, and cedar pollen so far this spring," said Daniel Coates, director of aerobiology research for ARL. "The delayed onset is about to change as warmer temperatures arrive, triggering a rapid increase in airborne allergens."

Microbiologist and immunologist Stephen Tuffs explained that those with seasonal allergies have an antibody called IgE that binds to allergens like pollen, which then causes an immune response.

"These molecules then bind to other cells that make things called histamines, and histamines are chemical signals to our immune system to make what we call inflammatory signals," he explained. "They tell other cells to start making responses to deal with what they think is a pathogen. But it's actually just against a harmless environmental thing like pollen."

The immune response from pollen can be very specific, he said, in that people can react differently to different types of pollen, depending on what time of year it is, and where they are.

"I'm allergic to birch and grass pollen. So when grass pollen is up, I'm less allergic to tree pollen, but when the grass pollen is high, I really need to double up my antihistamine doses," he said. "'I've lived in Ontario before, and then my allergy season was kind of in September, but in B.C., it's a little bit more middle of summer."

As pollen is expected to surge, Tuffs recommends those looking to manage their allergies talk with their allergist.