4. Swollen Leg or Arm
Perhaps one of the first outwardly noticeable signs that a blood clot has formed is swelling in the general area. This usually occurs in an arm or leg and is most likely caused by deep vein thrombosis (DVT).
However, in many cases of DVT, there will be no visible signs at all, which in turn increases the risk of the clot worsening and/or dislodging and moving to other more vital parts of the body such as the lungs. In this case, it can cause a pulmonary embolism as described above in the section on unusual coughing.
However, when swelling does occur and is associated with DVT in the leg it will often be visible in the calf, which may also become painful and more sensitive when touched. The affected area may also feel warmer than the surrounding skin. Swelling could also occur in the thigh or lower down toward the ankles and feet.