There was a time when Debbie Watson could count on a long break from allergies as autumn rolled in.
Not so much anymore.
“It used to be spring and summer were really bad and we had a break in winter. Now it seems like there's not as much of a break,” Watson said last week as she and her 8-year-old got allergy shots.
Watson is on to something.
Spring allergies may be around the corner, but it's ragweed, that late-summer scourge, that's making headlines.
For the first time, a study has documented that the season for ragweed, the most debilitating of plant allergens, is lengthening in North America.
The Omaha area was one of 10 sites providing data for the study. From 1995 through 2009, the season became longer, averaging 11 additional days. Farther north, the season lengthened even more.
The findings are consistent with what can be expected as a result of climate change, the report notes, and could foretell a longer allergy season in years to come.
“We were surprised ... by how much change had been seen over such a short period,” said Kim Knowlton, one of the lead authors and a health scientist at Columbia University and senior scientist at the Natural Resources Defense Council.
Dr. Linda Ford, an allergist with the Asthma & Allergy Center formerly in Papillion and now in Bellevue, said she has seen the effects of longer seasons on her patients. Her center provided the Omaha-area pollen counts for the study, published in the Proceedings of the National Academy of Sciences.
The start and peak of ragweed season have remained fairly predictable, Ford said. It typically starts in early August and peaks around Labor Day.
Around 1995, the season typically ended within the first two weeks of October, according to the study. By 2009, the end had shifted to the last half of the month.
Ford and Dr. Thomas Casale, chief of allergy and immunology at Creighton University, both said they're seeing the season extend to later in the fall.
“Our falls are warmer than they used to be, our frosts have been delayed. If you think about it, you shouldn't be surprised, because we've lived it,” said Ford, a report co-author.
Research has shown that the effects of climate change will be more noticeable the farther north one travels. A similar pattern was found in this study, Knowlton said.
In Oklahoma City, the allergy season lengthened by about a day from 1995 through 2009. In Minneapolis, it grew by an average of 16 days and in Saskatoon, Canada, by 27 days.
At least 10 percent of the U.S. population is ragweed sensitive, according to a skin test survey cited by the study.
People can be nearly incapacitated by the allergy, and their productivity at work and school suffers, Ford and Casale said. Some over-the-counter antihistamines can further impair people because they have a sedative effect.
A study that Casale participated in found that about 20 percent of people with hay fever or rhinitis, an allergic inflammation of the nasal lining, have symptoms despite medication.
Health scientists distinguish between the lengthening of the allergy season and the fact that more people are getting allergies. The two may or may not be related, Casale said.
The study doesn't directly identify climate change as the definitive cause for the lengthening allergy season. However, Casale and Ford said addressing climate change is a public health matter.
Watson, of Papillion, agreed. Her husband and other family members and friends have allergies, which leave them run-down and feeling like they have a constant cold.
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Contact the writer:
402-444-1102, nancy.gaarder@owh.com
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