Red nevus on the face, generally refers to tiny vascular nevus appearing on the surface of the skin, and the cause of the onset is related to heredity, congenital developmental abnormalities and other factors. 1. Hereditary factors. Microvascular nevus is also called microvascular tumor, the disease has certain hereditary tendency, so if there are people with similar disease in the family, the incidence rate of their children will be significantly higher. 2. Congenital developmental abnormality. Microvascular nevus is a kind of benign tumor caused by abnormal proliferation or differentiation of vascular endothelial cells in the process of embryonic development, which usually grows slowly and will not cause serious impact on the body. As for the present situation, since the etiology and pathogenesis of hemangioma are not very clear, the specific situation needs to be analyzed by combining various factors.