10 Warning Signs of a Blood Clot in the Leg
A blood clot in a deep vein of the leg is called deep vein thrombosis (DVT). It can become dangerous if part of the clot travels to the lungs and causes a pulmonary embolism.
Common warning signs include:
- Swelling in one leg — especially sudden swelling that affects the calf or thigh.
- Leg pain or tenderness — often felt in the calf and sometimes worse when walking or standing.
- Warmth — the affected area may feel noticeably warmer than the surrounding skin.
- Red or discolored skin — the leg may appear red, purple, or darker than usual.
- A feeling of heaviness or tightness in the affected leg.
- Enlarged or prominent veins that may appear suddenly.
- Pain when touching the calf or surrounding area.
- Unexplained cramping or aching in one leg that doesn’t go away.
- Swelling or discomfort that develops without an obvious injury, particularly after prolonged sitting, travel, surgery, or hospitalization.
- Symptoms that worsen over hours or days rather than improving normally.
Important: DVT can sometimes occur with few or no noticeable symptoms, so symptoms alone cannot confirm a clot.
Seek emergency care immediately if you have
- Sudden shortness of breath
- Chest pain, particularly pain that worsens with breathing
- Coughing up blood
- Fainting or severe dizziness
- A rapid or irregular heartbeat
These can be signs of a pulmonary embolism, which requires urgent medical attention.
If you have new one-sided leg swelling, pain, warmth, or discoloration, especially if you have risk factors for blood clots, it’s important to seek prompt medical evaluation rather than trying to diagnose it at home.
