A blood clot in the leg—most commonly deep vein thrombosis (DVT)—can be serious because a clot may travel to the lungs and cause a pulmonary embolism. Knowing the warning signs can help you seek care early.
10 possible warning signs of a blood clot in the leg
- Swelling in one leg
- Often occurs in the calf, ankle, or entire leg and may appear suddenly.
- Pain or tenderness
- May feel like a cramp, soreness, or aching, especially in the calf or thigh.
- Warmth over the affected area
- The skin over the clot may feel warmer than the other leg.
- Redness or discoloration
- The skin may look red, darker, or irritated.
- A feeling of heaviness or tightness
- The leg may feel unusually full, tight, or uncomfortable.
- Pain that worsens when walking or standing
- Movement may increase discomfort in some people.
- Visible changes in surface veins
- Veins may appear more prominent or swollen.
- Unexplained leg fatigue
- The affected leg may feel unusually tired or weak.
- Swelling that affects only one side
- One-sided symptoms are more concerning than equal swelling in both legs.
- Sudden worsening of symptoms
- Rapid changes should be evaluated promptly.
Seek emergency help immediately if you have possible signs of a clot plus:
- Sudden shortness of breath.
- Chest pain (especially with deep breathing).
- Coughing up blood.
- Rapid heartbeat, fainting, or severe dizziness.
Who is at higher risk?
Risk increases with factors such as:
- Recent surgery or hospitalization.
- Long periods of immobility (such as long travel or bed rest).
- Previous blood clots.
- Certain cancers.
- Pregnancy or the postpartum period.
- Smoking.
- Obesity.
- Some hormone-based medications.
A leg clot cannot be confirmed by symptoms alone—a healthcare professional may need tests such as an ultrasound.
If you are asking because you currently have leg symptoms, tell me:
- Which leg is affected?
- Is there swelling, pain, redness, or warmth?
- Did it start suddenly?
- Do you have shortness of breath or chest pain?
