Cetirizine inhibits bradykinin-induced cutaneous wheal and flare in atopicand healthy subjects

Background: Kinins are vasoactive mediators involved in allergic reactions. When applied on the skin or in the nose, bradykinin (BK) elicits inflammat ion that is poorly affected by previous H-1-blockade. The aim of this study was to compare the possible effect of cetirizine (an H-1-antagonist) on wh eal and flare responses to BK, histamine, and compound 48/80 in atopic and healthy subjects. Methods: In a randomized, double-blind, crossover study, eight atopic and e ight healthy subjects received cetirizine (10 mg/day) or placebo for 3 days before cutaneous tests. Intradermal tests (IDT) and prick tests (PT) were performed with BK (20 nmol/ml for IDT and 20 mu mol/ml for PT), histamine ( 100 mu g/ml IDT and 100 mg/ml PT), and compound 48/80 (100 mu g/ml IDT and 100 mg/ml PT) as positive controls and saline as negative control. The skin responses were monitored by measurement of wheal and flare areas. Results: BK, histamine, and 48/80 induced wheal and flare reactions in all placebo-treated subjects. Histamine elicited larger wheal and flare reactio ns than BK and 48/80. IDT with BK induced four- to sixfold larger wheal and flare reaction than PT, No differences in BK-induced wheal and hare were o bserved between atopic and healthy subjects. In atopic subjects, cetirizine induced a significant reduction of flare reactions after the BK test (80% for IDT, and 94% for PT [P < 0.01]), Moreover, cetirizine reduced significa ntly BK-induced wheals by 70% for IDT (P < 0.01) and 65% for PT (P < 0.01). A similar inhibiting effect of cetirizine was also observed in healthy sub jects. Conclusions: These findings showed that the wheal and flare reactions induc ed by BK challenge were markedly inhibited by previous intake of cetirizine . The mechanism by which this effect is mediated cannot be established at p resent.