Symptoms of DVT may include pain, swelling, tenderness, discoloration or redness of the affected area, and skin that is warm to the touch. However, as many as half of all DVT episodes produce minimal symptoms or are completely "silent."

Because a number of other conditions -- including muscle strains, skin infections, and phlebitis (inflammation of veins) -- display symptoms similar to those of DVT, the condition may be difficult to diagnose without specific tests.

DVT can occur in almost anyone. However, certain individuals may be at increased risk. Risk factors include but are not limited to:

• Surgery

• Restricted mobility

• Congestive heart failure

• Cancer

• Respiratory failure

• Infectious disease

• Age over 40

• Overweight/obesity

• Smoking

• Prior or family history of venous thromboembolism (blood clot in a vein)