Why have I developed allergies all of a sudden?

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Why some people develop allergies later in life remains largely unknown

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You might have spent much of your life counting your blessings that you made it well into adulthood without an allergy, then one spring or summer, the sniffles start, timed with the pollen.

What happened? After all, you’ve never had allergies before. Why do you suddenly have them now?

If you’re looking for answers, unfortunately, scientists say the mechanism whereby a non-allergy sufferer may suddenly develop allergies later is still something of a mystery.

“We don’t understand why allergies can present in some people very early on in life, or the larger percent of allergic people early on in life, and some later,” Dr. Harissios Vliagoftis, an allergist who is a professor at the University of Alberta’s Faculty of Medicine, told The Weather Network.

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Image: Getty Images

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Vliagoftis says scientists already know that many people can be sensitized to allergens such as pollen, and have the ability to develop allergies, but regardless of the age where full-blown allergies develop, there is usually some kind of trigger. It is that trigger, Vliagoftis says, that is still largely unknown.

Even for groups that moved from an area with one kind of pollen, into a new area with a kind of pollen they’d never encountered before, Vliagoftis says it does take a few years of sensitization before allergy symptoms actually appear, by this same, as-yet unexplained mechanism

“We know how sensitization happens, and we know a lot of the genetic factors that go into the process,” he says. “But how the actual final trigger [works], if there is one, we’re not clear.”

Without knowing that, Vliagoftis says that makes it hard, if not impossible, to advise people on what to do to reduce the risk of developing allergies.

“We have a lot of things we can do after they develop allergies, you know, we have very good medication these days, and very good ways to improve symptoms,” he says. “But advising people on how to prevent allergies, especially in older ages, we have no idea. Even for kids, its very difficult to advise adults how to decrease allergies in kids.”