A Study on Anlaysis of Patch Test Positive Reactivity according to the Reading Time with T.R.U.E. TEST(R) / 대한피부과학회지

ABSTRACT

BACKGROUND: The patch test is widely used for diagnosis of allergic contact dermatitis. However, nearly half of positive reactions can be observed only on day 2 or day 4 and it is difficult to interpret these reactions. OBJECTIVE: The purpose of this study is to assess the frequency of transient and delayed reactions in TRUE-test and detect common antigens that provoke these reactions. METHODS: A total of 311 patients with allergic contact dermatitis were evaluated by TRUE-test between Jan 2007 and December 2011. Records of patch test results of day 2 and day 4 were reviewed and analyzed. RESULTS: A total 311 cases of T.R.U.E. TEST(R) records (male 79, female 232) were analyzed. Persistent reactions were observed in 80.1% patients tested, transient reactions were observed in 18.3%, and delayed reaction in 5%. Frequent allergens which showed transient reactions were cobalt dichloride (2.9%), nickel sulfate (2.2%), thiomersal (1.9%), and carba mix (1.6%), in order of frequency. Allergens which showed delayed reactions were nickel sulfate (0.3%), fragrance mix (0.3%), p-tert-butylphenol formaldehyde resin (0.43). CONCLUSION: Our results showed a relatively high frequency of transient reaction in T.R.U.E. TEST(R). This suggests that additional reading at day 4 in the patch test would be of value.