The syndrome differentiation of purpura should distinguish asthenia from sthenia, and mild cases from severe ones. It is clinically divided into four syndromes of wind and heat impairing collaterals, bleeding due to blood heat, failure of qi to keep blood circulating intravascularly and hyperactive fire due to yin deficiency. The symptoms of wind and heat impairing collaterals commonly include abrupt onset first followed by symptoms of exterior syndrome of wind and heat, then by skin purpura mainly on lower limbs and buttocks with bright red colour, concurrent itching, etc.

The symptoms of bleeding due to blood heat commonly include abrupt attack, skin petechiae and ecchymoses, even patches of petechiae or ecchymoses with purplish red and concurrent symptoms of excessive heat affecting blood; the symptoms of failure of qi to keep blood circulating intravascularly commonly include repeated onset of purpura, purplish ecchymoses and petechiae and concurrent symptoms of qi deficiency of the spleen; the symptoms of hyperactive fire due to yin deficiency commonly include intermittent purpura, concurrent lingering nasal and gum bleeding and symptoms of internal heat due to yin deficiency.