The causes of rough and black ankle skin include poor blood circulation, post-inflammatory hyperpigmentation, and frequent friction. 1. Poor blood circulation: due to varicose veins and thrombosis in the lower limbs, resulting in poor blood circulation in the lower limbs, the skin at the end of the ischemia and lack of oxygen, which leads to roughness and blackness of the skin at the end of the patient’s skin and other skin symptoms. 2. Post-inflammatory hyperpigmentation: If the skin at the ankle suffers from inflammatory skin diseases such as eczema dermatitis, hyperpigmentation and skin roughness may remain after healing. 3. Frequent friction: If the shoes and socks do not fit the feet, their frequent friction with the ankle skin will cause the skin at the ankle to be rough and black. If the patient has rough and black ankle skin, it is recommended that the patient go to the hospital in time to improve the relevant examination, to clarify the cause of the disease, and follow the doctor’s instructions for treatment.