Elderly heel blackening may be related to trauma, purpura, lower extremity venous thrombosis and eczema and other diseases. 1. Trauma: the process of trauma may damage the local blood vessels, the blood is not discharged in time and the formation of bruises, the skin surface will be manifested as bruises or black phenomenon. 2. Purpura: due to a variety of reasons leading to structural or functional abnormalities of the blood vessel wall, platelet count reduction, as well as other coagulation disorders resulting in blood vessel rupture and bleeding, in the clinic, bruises will be formed, manifested as black skin. 3. Lower extremity venous thrombosis: due to venous thrombosis, it will affect the blood return of the lower extremity, so that the blood will be stagnant, and may even form some superficial collateral circulation, from the appearance of the skin will appear black. 4. Chronic eczema is a chronic inflammatory skin disease, due to a long period of time, the local skin will form a certain melanin deposition. If there is a blackened heel in the elderly, it is recommended to go to the hospital in a timely manner, standardized treatment under the guidance of the doctor.