Activation of coagulation in chronic urticaria in relation to disease severity and activity.

Background: The pathogenesis of chronic urticaria is incompletely understood. There is growing interest in the role of the coagulation cascade in chronic urticaria. We aimed to assess the possible activation of the coagulation cascade in chronic spontaneous urticaria (CSU) in relation to disease severity and activity.

Methods: This study was conducted on 30 patients with active CSU and 30 apparently healthy individuals as controls. Patients with acute urticaria, physical urticaria, or any form of urticaria other than spontaneous urticaria were excluded. Plasma levels of D-dimer and activated factor VII (FVIIa) were measured by ELISA at baseline for all recruited patients and controls. In addition, they were measured for CSU patients after complete disease remission.

Results: Plasma levels of D-dimer and FVIIa were significantly higher among patients with active CSU than among healthy controls. D-dimer levels were lowest among patients with grade 1 severity and highest among those with grade 4 severity. Factor VIIa levels did not differ significantly according to disease severity grades. After complete disease remission, there was a significant dramatic drop in levels of D-dimer and FVIIa among patients.

Conclusion: We conclude that activation of the coagulation cascade occurs in CSU, and we demonstrate the novel finding that activated factor VII levels are significantly reduced after medical therapy, confirming the implication of the extrinsic pathway activation in CSU. Future controlled studies may investigate the role of anticoagulant therapy in refractory chronic urticaria.