Blood clots can form in the superficial veins of the leg, causing superficial or deep vein thrombophlebitis, or in the arteries. The normal function of a blood clot is to stop bleeding after a cut or other injury. Blood clots can form whenever blood flow is sluggish or the vessels are damaged. Anyone at any age can form clots, but a number of risk factors exist, including smoking, cancer, obesity, dehydration, inactivity, pregnancy, surgery, trauma and age greater than 60. Certain medications, including birth control pills and hormone replacement therapy, increase the risk. Although many patients are asymptomatic, individuals who notice a change in one leg, pain or more serious symptoms should seek medical attention immediately. Blood clots that form in the blood vessels can be dangerous because they can break off and travel to other parts of the body, including the lungs, heart and brain, causing life-threatening strokes, heart attacks and pulmonary emboli.
Change in Appearance
The first signs of a blood clot may be changes to the appearance and temperature of one leg. When the blood in a vein clots, the skin over the affected area becomes red, warm and swollen, and the vein feels hard under the skin. The entire leg may become swollen as well. The unaffected leg will not change in appearance or temperature.The health-care provider often is able to make the diagnosis based on the appearance of the extremity and medical history alone.
Discomfort
The patient may complain of tenderness or soreness in one leg, or the pain may be severe. Pain is most noticeable when the patient stands or walks.
Test Results
Diagnostic testing can confirm the presence of blood clots in the leg. A Doppler ultrasound or venography--special x-rays using contrast medium--can identify blockage in a vein. Blood tests can be used to detect hypercoagulability, or excessive clotting of the blood.
Severe Symptoms
Patients with localized symptoms and pain who develop a fever, shortness of breath, pain with deep breathing, rapid breathing, fast heart rate or begins coughing up blood should seek emergency medical treatment. These signs may indicate a pulmonary embolism, a deep vein thrombosis that has dislodged and travel through the veins to the lung, according to the Mayo Clinic.
Long-Term Symptoms
Approximately 1/3 of patients with deep vein thrombosis experience long-term complications, according to Centers for Disease Control and Prevention. These individuals complain of pain, discoloration, swelling and scaling in the affected part of the body. The symptoms can be severe enough to cause disability.
