What causes a blood vessel in left leg to pop?

Vein disease: When patients have a genetic disease called venous insufficiency, they have venous hypertension and a backward flow of blood called reflux... This causes dilatation of veins, and thins out the overlying skin until the vein gets inflamed or ruptures. The leg eould need a compression wrap or even a suture and compression until the underlying condition can be treated either done in office.