"For new allergens, yes," Katial said. "You most likely won't manifest symptoms in the first year."
For allergies to start triggering symptoms, you need a first exposure to sensitize the immune system, with further exposures triggering the allergic reaction.
So why does it take a whole year for the symptoms to show?
"It has to do with when the pollens are out, when the allergens are out," Dalan said.
He noted, for example, that ragweed is only around for two months, which may not be enough to trigger the allergies.
Also, he noted, the amount of allergen in the air and your body's reaction may not be enough for you to notice.
"It's personal factors: your personal space and the abundance of the pollens around them in a given year," he said.
For that reason, it may take even longer to discover you have a seasonal allergy.
Dalan gave an example from one study in Minnesota in which identical twins had been split up after their parents' divorce, with one staying in the state and the other sister moving to Honolulu.
The Minnesota sister developed a ragweed allergy, but her sister did not, initially.
But when they both went to the University of Minnesota, the sister who had lived in Hawaii was diagnosed with the allergy her senior year.
"Some of those things are the patient's perception," Dalan said. "She probably developed it in the second or third year."
However, if symptoms aren't bad enough, a person may not be diagnosed with a seasonal allergy when they first develop it.
Getting a pet with shorter hair won't necessarily alleviate your allergy problems, because hair isn't the source of your reaction.
"It doesn't matter," Dalan said of a pet's hair length. "It's not the hair that's the problem; it's the saliva that's being excreted by the animal."
Animals lick themselves in order to stay clean, and that ultimately leads the allergens from the pet to be released into the air.
Katial said that in addition to the saliva, the animal's pelt, or skin, could also be an allergen source.
He added, however, that shedding enhances how much the allergen is carried throughout the house -- a problem more affected by cleaning than by the animal.
"If they're indoors, they still release allergen, hair or not," Katial said.
Not only are flowers nice to look at and a pleasing gift, but the tears they cause are for the most part tears of appreciation, not allergies.
Fortunately for the stop-and-smell-the-roses mindset, flowers evolved to have bees transport the pollen they need to spread to reproduce.
Trees, meanwhile, use the wind, and the presence of this pollen in the air is what tends to cause sniffling each spring.
While flower allergies aren't unheard of, trees and grass tend to be the primary culprits. So you may have less to worry about when you pick up a bouquet for a seasonal allergy sufferer.
"They may look nice and you can see the pollens, but those typically aren't allergenic," Dalan said.
With a little understanding of plant reproduction, the reason this is a myth becomes clear relatively quickly.