Red blood vessels generally refers to capillary dilatation, most patients thigh capillary dilatation does not have harm, a few patients will appear to affect aesthetics, pain and other hazards, if the visceral bleeding, purpura and other conditions lead to thigh red blood vessels will be harmful to the body. The majority of patients thigh capillary dilatation will generally be manifested as skin erythema, there will be no other uncomfortable symptoms, which may feel the impact on aesthetics. A small number of patients with capillary dilatation of the thigh area for a long time, may cause local pain, itching. In addition, if it is internal bleeding, purpura and other diseases caused by thigh erythema, may be harmful to the body, serious is easy to life-threatening. Most thigh capillarisations are not harmful to the body, and a few serious thigh capillarisations are more harmful to the body.