So, many people will likely find the weeks ahead a pain in the nose.
"It is going to be a brisk and abrupt allergy season," said Leonard Bielory, director of the Allergy Research Center at the University of Medicine and Dentistry of New Jersey.
After brief relief, courtesy of Friday's storm, tree pollen counts are surging again, said Donald Dvorin, an allergist who practices at the Asthma Center in Philadelphia and South Jersey.
And next week probably will be prime time for tree pollen, said Dvorin, who samples air in the Philadelphia area.
Soon thereafter, he said, grasses will take center stage. The moist soil could generate a robust crop of grass, sending prodigious amounts of pollen into the air.
More people in an annual health survey have been reporting allergy symptoms since 1991, according to the Philadelphia Health Management Corp., a public health research group.
About 31 percent of adults in Southeastern Pennsylvania surveyed last summer reported they suffered from at least one allergy, which could include anything from hay fever to bee stings. The data indicate the figure has climbed from 26 percent in 1991.
"That increase sounds impressive," said Martha V. White, director of research at the Institute for Asthma and Allergy in Wheaton, Md., a large group practice. "Any time you have something like that, you have to wonder why something like that is happening."
Researchers suggest that the prevalence of allergies is climbing in most industrialized countries. An estimated 40 million to 50 million people in the United States may be affected by some type of allergen - including pollens, dust mites and molds, according to the American Academy of Allergy, Asthma and Immunology.
Allergies can lead to such medical problems as asthma and sinus infections.
"On the ground, we are seeing more sinus and allergy symptoms," said Dvorin, who is a certified pollen counter for the National Allergy Bureau. "The trend is way up in the last four or five years."
The trend is not fully understood, but many experts believe it is partly explained by the hygiene hypothesis. Avoiding germs has a downside, the theory suggests, because children do not have the same opportunity to strengthen their immune systems as they did when they routinely played in the dirt and lived among farm animals. Absent an adequate workout, the immune system is more easily stimulated by exposure to pollen, pet dander or other allergens.
Experts say they believe that the reasons for the allergy rise also include air pollution and crowded living conditions.
"We are finding that it is an interesting combination of exposure and genes that helps play a role in developing allergies," White said.
Lynn Kotranski, a Philadelphia Health Management vice president who oversaw the group's survey, can mark the onset of allergy season by her symptoms: stuffiness, watery eyes and a sore throat. Her symptoms arrived in early April, she said.
"As the buds start coming out, I develop sinus problems," said Kotranski, who is particularly affected by the oak tree in the front yard of her Mount Airy home.
Kotranski, whose group conducted telephone interviews with 13,000 people, said the survey draws attention to problems associated with allergies. For instance, the data also indicated that allergy sufferers were more likely to report that their overall health was fair or poor than those who did not have allergies.
Dvorin said such self-reported data can be tricky to decipher. Many people think they have allergies, he said, when they actually have chronic sinus disease that can be triggered by changes in temperature, barometric pressure or humidity.
Or they can have a different problem.
Lauren Athey, 23, an aspiring opera singer from Mount Royal, Gloucester County, thought she had seasonal allergies when she saw a Center City specialist last week and received a spectrum of allergy tests on her back. She was experiencing hoarseness, even losing her voice. The tests revealed she had a couple of mold allergies that appear to have set off asthma, she said.
"It was not what I expected to hear," she said. "I had assumed I had seasonal allergies."
Katie Dewees, 24, of Glenolden, Delaware County, said she battles throughout the year with allergies and asthma. When the seasons change, it's just tougher, she said.
Dewees just started running for exercise again. But "breathing is awful in this weather," she said.
Contact staff writer Marian Uhlman at 215-854-2473 or firstname.lastname@example.org.