Superficial vein thrombosis
A clot in the veins of the skin or fatty tissues of the arms or legs is called superficial venous thrombosis (SVT). Symptoms include a pink, tender lump under the skin above a vein. SVT is rarely life-threatening as it usually forms in small veins. Any thrombus that migrates from small veins is unlikely to block much blood flow to the lungs. However, one in five patients with SVT will also develop thrombus into deep veins (DVT), which is a much more serious condition. A venous color duplex ultrasound can help find DVT so they can be treated.