The effect of desloratadine on patch test reactions in Chinese patients.

Few data on the effect of antihistamines on patch test results in Chinese patients are currently available. To evaluate the effect of desloratadine on patch test reactions. Patients known to have at least one strongly positive (+ +) test with an allergen were re-patch tested after 14 to 70 days (average time interval 26.3 days) of administering oral desloratadine 5 mg twice a day for 5 days before and during the test. Patch testing was performed with the previously recognized allergen according to the guidelines of the ICDRG. The -to + + + system was converted into numeric values (0, 1, 2, 3, 4) for statistic evaluation. Of the 58 chambers (47 patients), which were all strongly positive (+ +) during the 1st patch test, the situation was unchanged in 51 chambers; 4 + reactions and 2 + + + reactions were observed; and 1 chamber was negative. There was no statistically significant difference when comparing the scores of the 1st assessment with those of the 2nd (p = 0.206). If the patch test reaction of the patient who dropped out of the trial had changed from strongly positive (+ +) to negative, there would still have been no statistically significant difference between the score of the 1st assessment with those of the 2nd ( p = 0.107). The reaction of a patch test is not hampered by doubling dose of desloratadine. The anti-inflammatory effects of desloratadine on patch test reaction may be limited.