Changes in hemorrheology in urticaria.

Hemorrheology was studied in 41 cases of urticaria, and platelet aggregation function in 37 cases. The whole blood viscosity in low shearing stress, plasma viscosity, fibrinogen level and platelet aggregation were found to be markedly increased (P less than 0.05 - P less than 0.005). The cause of high blood viscosity is discussed. It is considered as the results of high plasma viscosity and increased RBC aggregation. The hemorrheological changes coincided with the hemodynamic changes seen in cutaneous microcirculation: slow granular blood stream, and aggregation of erythrocytes.