Acrocyanosis, also known as cyanosis of the hands and feet, is a peripheral vascular functional disease of unknown cause, characterized by symmetrical and persistent cyanosis of the hands and feet. The age of onset is mostly around 20 years old, more common in young women, and rarely seen in men. Symptoms tend to ease after middle age, but some persist. The incidence rate is higher in patients with mental disorders. Patients are thin and often report being afraid of cold all over the body. The skin of the hands and feet is cyanotic, the skin temperature is significantly lower (cold to the touch), and the hands are swollen. This disease worsens in cold seasons and when the limbs are drooping, and is relieved in warm seasons and when the hands are raised. Massaging the hands and feet can reduce the cyanosis or restore normal skin color.