The condition of bloodshot skin is considered to be related to capillary dilatation, which is also commonly known as redness, and is considered to be related to genetic factors, sun exposure, use of hormones, trauma and other factors. 1. Genetic factors: some patients may have a family history of capillary dilatation, so it suggests that the disease may be related to genetic factors. 2. Sun exposure factors: long-term exposure to sunlight, or living in a strong ultraviolet environment, such as Tibet, exposure to more ultraviolet rays, which can easily lead to the destruction of the skin stratum corneum, thus causing capillary expansion, so that the skin appears red blood. 3. Use of hormones: If you use cosmetics or medicines containing steroid hormones for a long time, it may also cause the phenomenon of skin redness due to hormonal stimulation. 4. Trauma: Trauma, cuts or improper squeezing stimulation may lead to the formation of dilated capillaries in the traumatized area. There may also be other causes of skin redness, which can be examined and removed by the doctor.