Leg Swelling That Won't Go Away: When to Seek Care

Urgent warning signs first

Call 911 for leg swelling accompanied by chest pain or shortness of breath. Seek same-day medical evaluation for sudden, unexplained swelling in one leg — especially with pain, redness, or warmth — which can signal a blood clot. The rest of this article is about swelling that persists without those red flags.

What can cause persistent swelling

• Vein disease — weakened valves let blood pool, and fluid collects in the lower legs (chronic venous insufficiency)
• Heart, kidney, or liver conditions — these change how the body handles fluid
• Medications — some blood pressure medicines and other drugs cause swelling as a side effect
• Lymphedema — impaired lymphatic drainage
• Blood clots — typically sudden and one-sided

A daily pattern or a sock indentation doesn't diagnose the cause — several of these can look similar from the outside.

How swelling is evaluated

Expect a history and examination that covers both legs, your medications, and your overall health. When vein disease is suspected, a duplex ultrasound checks how blood is moving through the leg veins. Depending on findings, additional evaluation may be needed — a venous study can't explain every case of swelling, and it's important the actual cause gets found.

Treatment depends on the cause

If the cause is venous, options range from compression and elevation to minimally invasive treatment of the underlying reflux. If the cause is elsewhere, the right move is treating that condition — which is why the evaluation comes first.

What to bring to your visit

A list of your medications, a note on whether one or both legs swell, when it started, and what makes it better or worse. Photos of the swelling at its worst can help too.