Frozen fingers are a pre-symptom of frostbite. The hands, feet, and ears are the terminal part of the body’s blood circulation and are the preferred site for frostbite. After late autumn, the temperature suddenly drops and the blood flow in the peripheral vessels becomes slow. When the temperature falls below 10 degrees Celsius, the small subcutaneous arteries in these areas contract in response to the cold, and venous reflux is poor, resulting in frostbite. In some cases, frostbite is caused by congenital mutations and narrowing of the blood vessels, resulting in poor blood flow. The cause of frostbite is the contraction of skin blood vessels due to cold, localized skin ischemia and hypoxia, and metabolic malfunction. In the long run, vascular paralysis and expansion, bruising, and plasma exudation cause local tissue edema, blister formation, tissue necrosis, and ulcer formation in the fingers. It occurs mostly in children and young women, and is more common in those with poor blood flow to the extremities and sweaty hands and feet, especially in those with inadequate nutrition or lack of qi and blood. Acrocyanosis, also known as hand and foot cyanosis, is a functional disorder of the peripheral vasculature characterized by symmetrical, persistent cyanosis of the hands and feet of unknown origin. It is a functional disease of the peripheral vasculature characterized by symmetrical, persistent cyanosis of the hands and feet of unknown origin. The symptoms tend to resolve after middle age, but some persist. The incidence is higher in patients with mental abnormalities. Patients are thin and often report a fear of cold, cyanosis of the skin of both hands and feet, a marked decrease in skin temperature (cold to the touch), and swelling of the hands, which is aggravated in the cold season and when the limbs are drooping and alleviated in the warm season and when the hands are raised.