Common symptoms of a blood clot in the leg include pain that feels like a bad cramp, swelling, reddish or bluish skin discoloration, and warmth radiating from the skin, according to the National Blood Clot Alliance. Deep vein thrombosis, or DVT, is another name for a blood clot.
Leg fatigue and visible veins on the surface of the leg are additional symptoms of a DVT, notes WebMD. The blood clot may block all of the vein in question, or only part of it, leading to intermittent symptoms in the early stages of the condition. Unfortunately, half of all DVTs have no symptoms.
A blood clot becomes a medical emergency when it breaks off and moves through the bloodstream, lodging in the lungs, states eMedicineHealth. This is called a pulmonary embolism. It causes severe breathing difficulty and can be fatal in minutes to hours, depending on the degree of blockage.
Risk factors for a blood clot include lengthy periods of bed rest, paralysis, recent injury or surgery, travel periods longer than four hours by car, plane, bus or train, and being overweight or obese, according to Mayo Clinic. For women, using hormonal birth control and carrying a pregnancy increase the risk for DVTs. Cancer, heart failure and inflammatory bowel disease are common diseases that also increase the risk for blood clots.