About 10 million canadians will sneeze, sniffle and wheeze their way through allergy season this spring, and the number of sufferers is on the rise.

“Allergies are a much bigger problem than they were 25 years ago, and they are becoming more complex,” says Kent HayGlass, professor and head of the department of immunology at the University of Manitoba in Winnipeg.

Not only do more people have allergy symptoms, he says, but the range of “triggers” is widening. And most doctors don’t have expertise in treating patients with allergies — if the patient bothers to seek treatment at all. HayGlass says many allergy sufferers don’t get medical advice because they don’t recognize the symptoms or because they don’t think the condition can be helped.

“There is no question that people are going undiagnosed,” he says. “This is an ongoing challenge for medical practitioners.”

An allergy is a hypersensitivity to an allergen, or trigger, that causes the immune system — which protects the body from disease and infection — to slip into defence mode. As a result, the immune system attacks the allergen in the same way it would a virus or bacteria. Common symptoms include everything from sneezing and watery eyes to rashes and hives. In more severe cases, symptoms may escalate to a dramatic drop in blood pressure or swelling airways, which could result in death. Strangely, allergies can develop or disappear at any time in life, just as symptoms can become milder or more severe with time.

Why do certain people suffer from allergies while others don’t? That’s the million-dollar question for researchers such as HayGlass, who has spent the past 26 years trying to understand the complex workings of the immune system.

“If I knew the answer, I’d be accepting the Nobel Prize right now,” he says.

What experts do know is that individuals are born with “unprimed” immune systems, meaning they are not programmed to fight infection. The more they are exposed to germs and infectious agents, however, the stronger they get. But, for reasons still not understood, some immune systems are more prone to hypersensitivity than others and can reject harmless things, such as grass pollen, resulting in allergic reactions.
Some people suffer from allergies all year long (dust mites and cat hair are the two most common offenders), while others only feel miserable in the spring when allergens are everywhere. There is no proven explanation of how and why allergies develop.

One theory, dubbed “the hygiene hypothesis,” suggests exposure to infectious agents early in life may actually boost the immune system’s activity and help it ward off allergic reactions later on.
Proponents of this theory argue that today’s sanitized world — cleaner water, antibacterial soap, household disinfectants — prevents the normal programming of the immune system, making it prone to allergic reactions. This theory helps explain studies showing that people who are exposed to more infectious agents in childhood (in daycare settings or exposure to germ-carrying siblings) are less likely to develop allergies as adults.

Another theory points to genetic predisposition. Essentially, just as people inherit genes that determine their hair and eye colour, they also inherit genes that determine the probability of developing allergies.

The good news is that while there is no cure for allergies, there are treatments that control the symptoms of some types of allergies, including over-the-counter antihistamines and allergy shots given by a doctor. For people suffering from asthma, a more severe form of allergy that causes chronic inflammation of the lungs and airways, there are corticosteroids, which help ease the inflammation.

Unfortunately, not all allergies are easily managed. An estimated 600,000 Canadians suffer from anaphylaxis, a potentially life-threatening allergic reaction to certain foods (peanuts and milk are the two main culprits), medications, insect venom or latex.
First-time reactions to these triggers may be
mild enough to go unnoticed, but a second or third could be deadly.

“With food allergies, a previous reaction does not predict how strong the next will be,” HayGlass says. “If you got away with it five times in the past, your next reaction could kill you.”

Anaphylaxis can be treated with a self-administered shot of epinephrine, a form of adrenaline, which helps reverse the reaction, but those living with severe allergies must monitor their surroundings at all times. But living with anaphylaxis isn’t a death sentence, experts say.