Antiinflammatory Properties of Cetirizine in a Human Contact Dermatitis Model. Clinical Evaluation of Patch Tests Is Not Hampered by Antihistamines.

Abstract

The aim of this double-blind;placebo-controlled;randomized;cross-over pilot study was to assess the antiinflammatory properties of cetirizine. A group of 27 patients with a positive patch test to an allergen consecutively received cetirizine 10 mg o.d. or placebo during a 14-day period;respectively. At day 11 of each period;patch testing was performed with the allergen. The image analysis showed a skin reaction significantly reduced under cetirizine (p = 0.03);but the clinical recording and the standardized chromatometry did not show any difference between groups. In the cross-over analysis the results of image analysis were influenced by the period;but this effect disappeared after adjustment of the ambient temperature during the 3 days of the test. These results demonstrate that cetirizine has an impact on the inflammatory process in a clinical model of cell-mediated allergic reaction;although this effect is only detected with a very sensitive technique. They also show that it is useless to stop antihistamines before patch testing;since clinical evaluation of tests is not hampered by a potent antihistamine. Additionally this study suggests that ambient temperature has an influence on the results of tests.