July 01, 2017

What causes legs to swell?

Q: My legs sometimes become swollen, but they don't hurt and it doesn't feel like anything else is wrong. Why might this be happening?

A: Mild leg swelling (edema) in both legs without any other symptoms is relatively common in older adults and usually not serious. Still, talking to your doctor is recommended, as the cause or causes can be serious.

Edema occurs when there's a disruption in the way your body balances fluids. This causes fluids to leak out of tiny blood vessels and build up in surrounding tissues. In addition to swelling, you may notice stretched or shiny skin or skin that stays indented after being pressed for at least five seconds.

Causes of mild edema in both legs without other symptoms may include:

  • Having consumed more salt than usual the day before
  • Being overweight
  • Standing or sitting for an extended period of time
  • A side effect of drugs such as calcium channel blockers, corticosteroids, nonsteroidal anti-inflammatory drugs and certain drugs for diabetes, particularly thiazolidinediones such as pioglitazone (Actos) and rosiglitazone (Avandia).

If your doctor diagnoses mild edema without a worrisome cause, treatment may involve:

  • Weight loss
  • Exercise, possibly including swimming pool exercises, in which water pressure on the legs redistributes fluids
  • Elevating the legs for an hour or two each day
  • Minimizing salt intake
  • Compression stockings to prevent fluid retention
  • Adjusting a medication that may be contributing to edema

Sometimes, edema can have a more serious underlying cause. This is particularly true with...