Aug 11 (AllergyHealthOnline) - More than one-half of the people in the United States test positive for sensitivity to one or more allergens when given an allergy skin test.

An allergy is an exaggerated or inappropriate reaction of the immune system to any substance that, in most people, causes no symptoms. An allergen is a substance your body perceives as a threat, triggering the immune system reaction.

Research gathered during the third National Health and Nutrition Examination Survey (NHANES III) indicated that 54.3 percent of people aged 6 to 59 years old in the U.S. tested positive for a reaction to one of 10 common allergens. The 10 common allergens included: dust mites, german cockroaches, cats, perennial rye, short ragweed, Bermuda grass, Russian thistle, White oak, Alternia alternata and peanuts.

Roughly 25 percent of the population had a positive response to either dust mite, rye ragweed or cockroach allergens. About nine percent of the population tested positive for a peanut allergy.

The NHANES III survey was conducted by the U.S. Centers for Disease Control and Prevention between 1988 and 1994. The purpose of the survey was to evaluate the health and nutritional status of the U.S. population. Roughly 10,500 people were involved in the allergy skin testing. Researchers from the National Institute of Health have only now been able to properly evaluate the NHANES III allergy data.

"There is still much we don't understand about why some people become sensitized to allergens and others do not," explained the paper's senior author, Darryl C. Zeldin, MD, in a recent press release. "Much more research is needed in order for us to understand the complex relationships between exposures to allergens, the development of allergic sensitization, and the onset and exacerbation of allergic diseases such as asthma."

The study was published in the August issue of the Journal of Allergy and Clinical Immunology.

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