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Mayo Clinic Study Implicates Fungus As Cause Of Chronic Sinusitis

ScienceDaily (Sep. 10, 1999) — "We can now begin to treat the cause of
the problem instead of the symptoms"

ROCHESTER, MINN. -- Mayo Clinic researchers say they have found the
cause of most chronic sinus infections -- an immune system response to
fungus. They say this discovery opens the door to the first effective
treatment for this problem, the most common chronic disease in the
United States.

An estimated 37 million people in the United States suffer from
chronic sinusitis, an inflammation of the membranes of the nose and
sinus cavity. Its incidence has been increasing steadily over the last
decade. Common symptoms are runny nose, nasal congestion, loss of
smell and headaches. Frequently the chronic inflammation leads to
polyps, small growths in the nasal passages which hinder breathing.

"Up to now, the cause of chronic sinusitis has not been known," say
the Mayo researchers: Drs. David Sherris, Eugene Kern and Jens
Ponikau , Mayo Clinic ear, nose and throat specialists. Their report
appears in the September issue of the journal Mayo Clinic

"Fungus allergy was thought to be involved in less than ten percent of
cases," says Dr. Sherris. "Our studies indicate that, in fact, fungus
is likely the cause of nearly all of these problems. And it is not an
allergic reaction, but an immune reaction."

The researchers studied 210 patients with chronic sinusitis. Using new
methods of collecting and testing mucus from the nose, they discovered
fungus in 96 percent of the patients' mucus. They identified a total
of 40 different kinds of fungi in these patients, with an average of
2.7 kinds per patient.

In a subset of 101 patients who had surgery to remove nasal polyps,
the researchers found eosinophils (a type of white blood cell
activated by the body's immune system) in the nasal tissue and mucus
of 96 percent of the patients.

The results, the researchers say, clearly portray a disease process in
which, in sensitive individuals, the body's immune system sends
eosinophils to attack fungi and the eosinophils irritate the membranes
in the nose. As long as fungi remain, so will the irritation.

"This a potential breakthrough that offers great hope for the millions
of people who suffer from this problem," says Dr. Kern. "We can now
begin to treat the cause of the problem instead of the symptoms."

More research is underway at Mayo Clinic to confirm that the immune
response to the fungus is the cause of the sinus inflammation. The
researchers are also working with pharmaceutical companies to set up
trials to test medications to control the fungus. They estimate that
it will be at least two years before a treatment will be widely

The researchers distinguish chronic sinusitis -- sinusitis that lasts
three months or longer -- from acute sinusitis, which lasts a month or
less. They say that the cause of the acute condition is usually a
bacterial infection.

Antibiotics and over-the-counter decongestants are widely used to
treat chronic sinusitis. In most cases, antibiotics are not effective
for chronic sinusitis because they target bacteria, not fungi. The
over-the-counter drugs may offer some relief of symptoms, but they
have no effect on the inflammation.

"Medications haven't worked for chronic sinusitis because we didn't
know what the cause of the problem was," says Dr. Ponikau. "Finally we
are on the trail of a treatment that may actually work."

Thousands of kinds of single-cell fungi (molds and yeasts) are found
everywhere in the world. Fungal spores (the reproductive part of the
organism) become airborne like pollen. Some people develop allergies
to fungi. The new evidence from the Mayo study suggests that many
people also develop a different kind of immune system response.


See Also:

Health & Medicine
•Immune System
•Cold and Flu
•Diseases and Conditions
•Kidney Disease
•Lung Disease

•Nasal congestion
•Hay fever
•Upper respiratory tract infection


Story Source:

The above story is reprinted (with editorial adaptations by
ScienceDaily staff) from materials provided by Mayo Clinic.