Lower extremity edema black, itching, flaky skin consider the possibility of long-term diabetes caused by or vasculitis. The above symptoms are usually caused by long-term chronic underlying diseases. The most common underlying diseases are diabetes and vasculitis. If the long-term blood sugar control is not good, it will lead to necrosis and inflammation of peripheral nerves and blood vessels, appearing edema, blackening, itching clinical symptoms, the first thing to do is to control the blood glucose level, active treatment of inflammation. The possibility of vasculitis in the elderly is also very common, vasculitis will be found along the blood vessels towards the color changes and inflammatory reaction, to find out the original cause of vasculitis, active control of inflammation treatment. No matter what the disease is, it is important to actively go to the hospital for examination and treatment.