CONTACT: C. LINDON LARSON
283 Medical Laboratories
Iowa City IA 52242
(319) 335-9569; fax (319) 335-8034
EDITORS: The University of Iowa will provide daily pollen counts beginning
Tuesday, August 12, and continuing throughout ragweed season. For daily counts,
call the UI pollen count information line at (319) 335-8964.
UI offers daily ragweed allergy forecasts
IOWA CITY, Iowa -- It's that time again. Watery eyes, scratchy throats, runny
noses and sneezing mark the beginning of ragweed season, a stretch of late
summer dreaded by millions of people with allergies.
Ragweed allergies -- also known as hay fever -- affect nearly 15 percent
of Americans. Iowa and other Midwestern states offer ideal conditions for
the ubiquitous ragweed plant, which releases its pollen into the air for about
six weeks starting in mid-August.
"Every year is a good year for ragweed and a bad year for people with
allergies," says Dr. John Weiler, professor of internal medicine at the
University of Iowa College of Medicine. "The plant always grows well
in Iowa, regardless of weather."
The chief culprits are actually two plants, Ambrosia artemisifolia,
or common ragweed, and Ambrosia trifida, best known as giant ragweed
or horseweed. Each year, more than 250,000 tons of their microscopic pollen
grains are blown about the United States.
Starting Tuesday, August 12, and continuing through the end of ragweed season
in late September, the UI College of Medicine will offer daily pollen counts
to help people with allergies gauge their symptoms.
A thin, transparent tube atop a building on the UI health science campus
collects airborne pollen grains that are measured by researchers. Though daily
counts record the amount of pollen detected over the previous 24 hours, they
are usually a good indicator of current conditions.
A pollen count of 200 or less is said to fall into the "comfort zone,"
meaning that most people will be free of allergy symptoms. The "discomfort
zone" includes counts from 220 to 1,000, and indicates that most people
with ragweed allergy will feel its effects. Counts greater than 1,000 -- the
"severe discomfort zone" -- mean serious symptoms in people who
are most sensitive to ragweed and milder reactions in those who seldom experience
symptoms at lower levels.
Allergies occur when the body's immune system overreacts to an otherwise
harmless substance like ragweed pollen. Inhaled pollen adheres to antibodies
produced by the body and triggers an immune reaction that causes respiratory
symptoms, or allergic rhinitis. During ragweed season, some people allergic
to the plant may also react to foods that contain similar proteins, including
chamomile, cantaloupe, honeydew and watermelon.
Allergy symptoms can be severe, even incapacitating, and avoiding pollen
on the worst days is the best way to prevent symptoms. "If possible,
stay indoors in air-conditioned areas, particularly in the early morning when
the ragweed plant produces most of its pollen," Weiler says. The safest
times to venture outside are in late evening or after a rainfall.
Since ragweed pollen clings to hair and clothes, washing one's hair before
bedtime may reduce symptoms, as can frequent vacuuming, dusting, and laundering
bedding. Contact lenses can increase eye irritation, so people with ragweed
allergies may want to avoid them on heavy pollen days.
Non-prescription antihistamines and nasal sprays may also provide relief,
but relying on sprays can bring additional problems. When overused, sprays
can cause swelling in the nose and mimic allergy symptoms.
Physicians can prescribe stronger medications for people with the worst symptoms.
For more information, consult your physician or other health care provider.