Purple capillaries may be a normal phenomenon, or it may be caused by capillary dilatation, vascular blockage and other reasons. 1. Normal phenomenon: patients with less fat, white skin, and superficial capillaries, blood oxygen saturation in different blood vessels will be different, so it may show purple, red and other colors, if there is no other adverse reaction, usually do not need treatment, is a normal phenomenon. 2. Capillary dilatation: capillary dilatation is usually caused by other diseases, such as cirrhosis of the liver, lupus erythematosus, hyperthyroidism, etc., or long-term hypoxia, prolonged exposure to the sun, exposure to relevant drugs, may also cause the skin mucous membrane capillary dilatation, showing a purple color. 3. Blood vessel blockage: Blood vessel blockage is usually caused by hardening of blood vessel wall, surgery, tumor, etc. When the plaque flows into the blood cavity, thrombus may be formed on the surface, which ultimately results in blood vessel blockage, so the symptom of purple capillaries may appear. It is recommended that patients should go to the hospital in time for consultation when they experience discomfort.