Purple feet may be caused by the following reasons: 1, subcutaneous bleeding, such bleeding is seen in the foot by a direct smash, or a serious sprain. Injuries such as soft tissue contusions and fractures may occur internally and can be accompanied by very severe subcutaneous bleeding. Due to hemoglobin-related changes, a purplish color is displayed on the surface of the skin. 2. Ischemic diseases of the lower extremities, such as deep vein thrombosis or stenosis of the aorta of the lower extremities. Both conditions can cause poor blood circulation in the lower extremities, resulting in purple, cold, and numb symptoms in the lower extremities. 3. Frostbite in the lower extremities, such as prolonged cold in the feet, may cause severe poor blood circulation, resulting in purple. 4. Severe hypoxia, such as asphyxia or severe cardiopulmonary-related diseases, can cause cyanosis at the ends of the extremities, i.e., in the feet and hands.