Chronic Sinusitis Caused by Fungus


It is not a cure for the common cold, but it may be almost as important. Researchers have found that chronic sinusitis, a condition that affects about 37 million people in the US, is apparently caused by an immune response to fungus. "This is a potential breakthrough that offers great hope for the millions of people who suffer from this problem," researchers led by Dr. Jens Ponikau say in a statement released by the Mayo Clinic in Rochester, Minnesota. "Up to now, the cause of chronic sinusitis has not been known."

Using a new technique for collecting and testing mucus, the researchers were able to show that 202 out of 210 patients with chronic sinusitis had fungi in their mucus. In addition, they detected eosinophils in the nasal tissues and mucus of almost all the patients from this group who underwent surgery for nasal polyps. Eosinophils are one type of white blood cell. They become especially prominent in the blood and tissues when the body responds to certain kinds of immune system challenges, such as the allergic response or parasitic infection.

What this means, concluded the researchers, is that "fungus is likely the cause of nearly all of these problems." They add, that it is not an allergic response, per se, but rather an immune reaction. The findings were reported in the September 1999 issue of the Mayo Clinic Proceedings.

In the past, less than 10% of cases of chronic sinusitis were believed to be caused by fungus allergy, explained the study authors. Though eosinophils were identified in nearly all the nasal tissues and mucus, the investigators found that most study subjects were not sensitive to immunoglobulin-E, suggesting that chronic sinusitis results from the body's immune response to the fungus. This non-allergic response would explain why antihistamines may fail to help people with chronic sinusitis.

Ponikau and colleagues suggest that the name be changed from allergic fungal sinusitis to eosinophilic fungal rhinosinusitis to reflect their findings as to the cause of this condition.

Source: Mayo Clinic Proceedings 1999;74:877-884.

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