Answered by SecondMedic Expert
Vascular Surgeon · Vascular Surgery
Verified
The most common reason for swelling in one leg is a problem with the veins. Vein problems can occur when the valves that keep blood flowing in one direction malfunction. This causes blood to back up and fluid to leak out of the veins and collect in the tissues of the leg.
Other causes of swelling in one leg include: heart failure, kidney failure, liver cirrhosis, and injury or infection. If you have any questions about why your leg swelled up, it is best to speak with a health care professional.
