Accuracy of patient prediction of allergy skin test results

Background: The ability of patients to self-diagnose allergy is unknown. Objective: To estimate the ability of patients to correctly predict the res ults of allergy skin tests. Methods: We conducted a structured interview of 86 patients with chronic rh initis or asthma undergoing aeroallergen skin tests. We asked, "Do you expe ct the skin tests to be positive or negative?" and "What do you expect the allergy tests to be positive for?" Responses to these questions were correl ated with the results of aeroallergen skin tests. Skin tests were performed using the prick technique and included cat, grass pollen, tree pollen, wee d pollen, dust mites, and molds. Results: Seventy-three participants provided usable responses. Of those wit h a positive skin test, the number (percentage) of participants who predict ed correctly was 10/18 (56%) for cat, 4/14 (29%) for tree, 7/26 (27%) for w eeds, 5/23 (22%) for dust mite, 2/12 (17%) for grass, and 1/8 (12%) for mol d. Of those with a negative skin test, the number (percentage) of participa nts who predicted correctly was 47/50 (94%) for dust mite, 51/59 (86%) for trees, 56/65 (86%) for mold, 52/61 (85%) for grass, 45/55 (82%) for cat, an d 38/47 (81%) for weeds. Conclusions: (1) Patients have limited ability to correctly predict positiv e skin tests to aeroallergen. (2) Patients are able to predict negative ski n tests with reasonable accuracy. (3) "What do you think you are allergic t o?" may be a good screening question for patients with asthma and rhinitis.