Severe CSU and Activation of the Coagulation/Fibrinolysis System: Clinical Aspects

Background. About 50% ofpatients with severe chronic spontaneous urticaria (CSU) show signs ofactivation of the coagulation/fibrinolysis system, but the clinical significance ofthis 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/f44/88; mean age 51, 5 years; range 14 - 89 years) with severe CSU (UAS-7 > 30) were included in a cross-sectional real life study. The study group was divided based on baseline D-dimerplasma levels, and comparedfor age, sex, disease duration, disease activity, CRP, thyroid autoimmunios total IgE, and atopic status. Results. Identical numbers ofpatients showed elevated and normal D-dimerplasma levels (50% and 50%, respectively). Patients showing elevated D-dimer levels were slightly older (p < 0.05), were morefrequentlyfemales (p < 0.05), had a longer disease duration (p < 0.01), and had a significantly higher prevalence ofelevated PCR (26/66 vs 4/66; p < 0.001). Conclusions. Only 50% ofpatients with severe CSU show elevated D-dimerplasma levels. The activation ofthe coagulation/fibrinolysis system is associated with a systemic inflammatory milieu, suliesting the existence ofa specificphenotype. Whether this reflects the existence ofdifferent endotypes in patients showing and not showing the activation ofthe coagulation cascade has still to be established.