Purpura is bleeding into the skin and mucous membranes. It appears as small hemorrhages that do not fade when pressure is applied. Small purpuric lesions, less than 2mm in diameter, are called petechiae, and larger lesions are called ecchymosis.

The most common cause of purpura is heat, which causes the blood to move recklessly and spill from the vessels. Qi deficiency, which fails to maintain the integrity of the vessels, and blood stasis can also cause purpura. When heat is involved, the purpura may also be raised and palpable.