Severe CSU and activation of the coagulation/fibrinolysis system: clinical aspects

Background. About 50% of patients with severe chronic spontaneous urticaria (CSU) show signs of activation of the coagulation/fibrinolysis system, but the clinical significance of this phenomenon is unclear. Objective. The present study compared patients with severe CSU showing and not showing elevated D-dimer plasma levels. Methods. 132 adult patients (m/f 44/88; mean age 51, 5 years; range 14 - 89 years) with severe CSU (UAS-7 major 30) were included in a cross-sectional, real life study. The study group was divided based on baseline D-dimer plasma levels, and compared for age, sex, disease duration, disease activity, CRP, thyroid autoimmunity, total IgE, and atopic status. Results. Identical numbers of patients showed elevated and normal D-dimer plasma levels (50% and 50%, respectively). Patients showing elevated D-dimer levels were slightly older (p minor 0.05), were more frequently females (p minor 0.05), had a longer disease duration (p minor 0.01), and had a significantly higher prevalence of elevated PCR (26/66 vs 4/66; p minor 0.001). Conclusions. Only 50% of patients with severe CSU show elevated D-dimer plasma levels. The activation of the coagulation/fibrinolysis system is associated with a systemic inflammatory milieu, suggesting the existence of a specific phenotype. Whether this reflects the existence of different endotypes in patients showing and not showing the activation of the coagulation cascade has still to be established.