The results of a skin test found that 54% of the US population aged 6 to 59 had a positive reaction to at least 1 of 10 common allergens. A positive result was determined by the size of a welt on the skin, compared with a prick from a negative control. Therefore, the positive group was more likely to have asthma, hay fever, or eczema. The findings were based on the Third National Health and Nutrition Examination Survey that included skin tests on 10,500 individuals between 1988 and 1994.
The government study indicated that 25% of the population tested positive for allergies to dust mites, perennial rye, ragweed, and cockroaches. Of the participants, only 9% had a peanut allergy. The researchers from the National Institute of Environmental Health Sciences and the National Institute of Allergy and Infectious Diseases also compared skin-test responses between the current survey and similar tests conducted in 1976-1980. The comparison showed that prevalence of sensitivity to the 6 allergens that were tested in both surveys was 2 to 5.5 times higher in the later round. The first survey tested 8 allergens. (The findings were reported in the Journal of Allergy and Clinical Immunology, August 2005.)