🦵 10 Warning Signs of a Blood Clot in the Leg

A blood clot in a deep vein is called deep vein thrombosis (DVT). It can become dangerous if part of the clot travels to the lungs and causes a pulmonary embolism. (NHLBI, NIH)

Possible warning signs include:

1. Swelling in one leg, particularly if it appears suddenly.
2. Pain or tenderness without an obvious injury.
3. Aching or cramping in the calf or thigh.
4. Unusual warmth in the affected area.
5. Red or discolored skin.
6. A feeling of heaviness or tightness in the leg.
7. Pain that becomes more noticeable when walking or standing.
8. Swelling accompanied by tenderness when touching the area.
9. Symptoms affecting one leg rather than both—although this isn’t always the case.
10. Sudden unexplained changes in the leg, especially when several of the symptoms above occur together.

The classic DVT symptoms are swelling, pain/tenderness, warmth, and redness or discoloration. Importantly, some people with DVT have no noticeable symptoms at all, so symptoms alone cannot confirm or exclude a clot. (NHLBI, NIH)

🚨 Know the emergency signs

If a clot travels to the lungs, symptoms can include sudden shortness of breath, chest pain that worsens with deep breathing or coughing, rapid heartbeat, coughing up blood, lightheadedness or fainting. This may be a pulmonary embolism and requires immediate emergency medical attention. (NHLBI, NIH)

Who is at higher risk?

Risk increases with factors such as recent surgery or hospitalization, prolonged immobility or long travel, cancer, previous blood clots, pregnancy/postpartum, estrogen-containing medicines, obesity, smoking and increasing age. (NHLBI, NIH)

Bottom line: Don’t try to diagnose a DVT at home. A swollen, painful, warm or discolored leg—especially when symptoms are new and unexplained—deserves prompt medical evaluation. Doctors may use blood tests and imaging such as an ultrasound to determine whether a clot is present. (NHLBI, NIH)