D-dimer levels decline after immunosuppressive treatment rather than anticoagulant treatment in severe autoimmune chronic spontaneous urticaria.

Summary: Chronic spontaneous urticaria (CSU) is a common dermatological condition presenting with wheals and/or angioedema for more than 6 weeks. The role of autoimmunity and inflammation in the pathogenesis of CSU have been studied, but the precise mechanism remains unknown. Association with coagulation cascade has been suggested based on the observations of increased coagulation indicators such as serum D-dimer levels. We report an omalizumab refractory case of severe CSU with high D-Dimer levels that declined only after disease remission with cyclosporine treatment but not with anticoagulation. Activation of coagulation cascade occurs secondary to the pro-inflammatory state in CSU patients and the correlation between D-dimer levels and disease activity may indicate the need for more studies to better understand the relationship of D-dimer levels and Omalizumab resistance. Clinicians should consider this relationship in CSU patients with significant D-dimer levels before considering treatment with anticoagulants.