Results of Using the Patch Test with Urushiol in Korea

Shin, Soo Jung; Kim, Chul Woo; Kim, Sang Seok

Abstract

BACKGROUND
Allergic contact dermatitis (ACD) due to urushiol is a relatively common phenomenon in Korea. However, there are no recent studies regarding the results of patch tests with urushiol in ACD patients.
OBJECTIVE
The purpose of this study was to analyze the results of the urushiol patch test, and to compare current urushiol sensitivity with findings from previous reports.
METHODS
Patch test with 0.002% urushiol allergen and a thin-layer rapid use epicutaneous (T.R.U.E.) patch test were performed in 200 patients (67 men and 133 women) who were suspected of having ACD, between July 2011 and July 2013. Patient demographic findings and patch test results were evaluated.
RESULTS
Positive reactions to urushiol were observed in 23 patients (11.5%), with a mean age (+/-standard deviation) of 61.4+/-10.8 years, which was significantly older than the mean age of 47.6+/-16.4 years of patients testing negative for urushiol sensitivity (p<0.001). Patients aged 50~59 years had the highest incidence of a positive reaction, and this difference in urushiol sensitivity according to age groups was statistically significant (p<0.005). A total of 8 (11.9%) of the 67 male patients, and 15 (11.3%) of the 133 female patients showed a positive reaction to urushiol. Of the 23 patients with a positive reaction to urushiol, 19 patients (82.6%) had at least one positive reaction to the T.R.U.E. test allergen, with p-phenylenediamine showing the highest sensitization rates (31.6%). The most frequently affected site in urushiol-positive patients was the face (39.1%).
CONCLUSION
Based on our study results, urushiol sensitivity among Korean ACD patients is a relatively common occurrence, and a patch test with urushiol would be helpful in identifying the causative allergen in ACD patients.