COLUMBUS, Ohio - A heads-up to people who suffer from allergy-like symptoms: Your sniffles and sneezes may not be due to allergies after all.
In a recent study of 246 patients, researchers found that nearly two out of three patients treated for allergies were not allergic.
"Millions of people suffer unnecessarily because they really don't have allergies," said Sheryl Szeinbach, a study co-author and a professor of pharmacy at Ohio State University. "They're often prescribed antihistamines that don't help the problem."
Szeinbach presented the findings March 28 in Philadelphia at the American College of Osteopathic Family Physicians' annual meeting.
The researchers used the ImmunoCAP allergy blood testing method to test patients' reactions to common external allergens, such as animal dander, pollen and mold. ImmunoCAP tests the reaction of immunoglobulin E (IgE) - a compound in the immune system - to specific allergens. IgE helps fight off toxins and also triggers allergic reactions.
The subjects in the current study first completed aquestionnaire on the severity of their allergy symptoms. The researchers followed the questionnaire with a blood test for common external allergens. All patients in the study had previously been diagnosed with allergies and were taking prescription antihistamines.
Sixty-five percent of the patients tested negative for allergies; the blood samples from only 35 percent of the subjects showed true allergic reactions. "This means that two-thirds of the patients were on the wrong kind of medication to start with," Szeinbach said. "And this led to other problems, such as an increased use of anti-depressants.
"As a population, people with allergies or allergy-like symptoms tend to use antidepressants at a higher rate, and we found that this rate was even higher in the group of patients that tested negative. These same patients also visited their doctor more often."
It's imperative that doctors have the right kinds of tools to diagnose allergies, Szeinbach says, and not all commercial tests are created equal. Allergy tests come in many shapes and forms. One of the better-known methods is the skin prick test. A drop of the allergen is placed on a patient's arm or back. The physician then pricks the skin through the drop, which allows the allergen to enter the body. The doctor and patient then wait for a reaction, which could indicate an allergy. But the accuracy of the skin prick test can range from 30 to 63 percent, Szeinbach said.
Allergy symptoms mimic the symptoms of other upper respiratory conditions that affect the nasal cavity and sinuses, such as a runny nose and eyes. Almost anything can cause allergy-type symptoms - perfumes, sinus infections, exercise, dust, cold air - whether it's an allergy or not.
"The message is simple: Physicians and consumers need to know that there is a reliable, accurate way to detect allergies," Szeinbach said. "Now even family physicians can easily know if a patient is allergic and what allergens trigger the reaction."
A grant from Pharmacia Diagnostics, the manufacturer of the ImmunoCAP test, supported the research.
Szeinbach co-authored the study with Mark Boye, a graduate student in the college of pharmacy at Ohio State; Pieter Muntendam of ProMedex; and Richard O'Connor of the Sharp Rees-Stealy medical group based in San Diego.
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