The appearance of red blood, may be related to capillary dilatation, the main causes include genetic factors, environmental factors, ultraviolet radiation, the use of drugs and other factors. 1. Genetic factors: primary capillary dilatation is related to congenital capillary development abnormalities and autosomal dominant inheritance, which may lead to the phenomenon of redness all over the body. 2. Environmental factors: prolonged exposure to thin air and hypoxia leads to an increase in the number of red blood cells in the blood, which stimulates compensatory expansion of blood vessels, resulting in the phenomenon of generalized red blood. 3. Ultraviolet radiation: prolonged exposure to strong ultraviolet rays, such as sun exposure, can lead to capillary expansion, which can also lead to the formation of generalized red blood. 4. Drug factors: prolonged abuse of drugs may lead to adverse drug reactions and thus the formation of generalized redness, such as the use of glucocorticoid drugs in large doses for a long time or the use of cosmetics containing glucocorticoid drugs. As there are many reasons affecting capillary dilatation, it is recommended that the patient go to the hospital and ask the doctor to analyze the situation after an interview.