A blood clot in a deep vein of the leg is called deep vein thrombosis (DVT). It can be serious because a clot may travel to the lungs and cause a pulmonary embolism, which can be life-threatening. Knowing the warning signs can help you seek care quickly.
10 Possible Warning Signs of a Blood Clot in the Leg
1. Swelling in one leg
- Swelling that appears suddenly, especially in one calf, ankle, or thigh, is a common DVT warning sign.
2. Leg pain or tenderness
- Pain may feel like a cramp, soreness, or aching—often in the calf or thigh.
- It may worsen when walking or standing.
3. Warmth in the affected area
- The skin over the clot may feel warmer than the surrounding area.
4. Redness or discoloration
- The skin may appear red, darker, or have a bluish tint near the affected area.
5. A feeling of heaviness or tightness
- Some people describe the leg as feeling full, heavy, or unusually tight.
6. Enlarged or more visible veins
- Surface veins may become more noticeable because blood flow is being affected.
7. Sudden changes in leg size
- One leg may look noticeably larger than the other.
8. Persistent discomfort without a clear injury
- Unexplained leg pain or swelling that does not improve with rest should be checked.
9. Shortness of breath or chest pain (emergency sign)
If a clot travels to the lungs, symptoms may include:
- Sudden difficulty breathing
- Chest pain (especially sharp pain that worsens with deep breaths)
- Rapid heartbeat
- Coughing, sometimes with blood
Call emergency services immediately if these occur.
10. Feeling faint or unusually weak
- Dizziness, fainting, or sudden weakness can be signs of a serious complication.
