Abstract
We assessed the diagnostic significance of 20-minute patch tests in immediate hypersensitivity by egg white comparing with prick tests. Forty-six subjects (male:female=25:21, median age±standard deviation=38.6±24.3 months, range; 11 to 124 months) were orally challenged with freeze-dried egg white in a double-blinded manner. We considered reactions of wheal positive in 20-minute patch tests. The reactions of wheal more than 3mm or erythema more than 10mm in a longer diameter were judged positive in prick tests. The agreement rate between 20-minute patch tests and oral challenge tests was 73.9%. In contrast, the rate between prick tests and oral challenge tests was 60.9%. We divided all subjects into two groups under and over three years of age. The results of 20-minute patch tests gave the best agreement rate in group aged three years or younger. Then we concluded that 20-minute patch tests, especially in children up to three of age, have a significant diagnostic value in immediate hypersensitivity by egg white.
