Usually purple blood in the ankle is mostly related to the expansion or breakage of ankle capillaries, commonly seen in varicose veins, ankle sprains, but some patients with vitamin C deficiency and coagulation system dysfunction diseases can also have this kind of performance, if the patient is unable to judge, if necessary, promptly seek medical attention, and here are several common cases specifically listed: 1. Varicose veins: usually seen in prolonged standing, heavy physical labor and some Special people, such as pregnant women, obese patients, because of their blood vessel wall elasticity, valve insufficiency, etc. can cause blood return obstruction, and the lower extremity venous pressure increases, resulting in ankle capillary dilation. When the capillaries are dilated, the oxygen saturation of the capillaries can be reduced, resulting in purple blood in the ankle. 2. Patients with this condition also have swollen and painful ankle joints; 3. Other reasons: if patients suffer from vitamin C deficiency, their capillary permeability increases, which can easily cause blood to leak out from inside to outside the blood vessels, thus causing purple blood in the ankle joints. In addition, patients with coagulation system dysfunction are also prone to these manifestations due to the lack of coagulation factors.