Swollen ankles are usually caused by fluid buildup in the lower legs, also called edema, and the most common reasons include standing or sitting too long, eating too much salt, pregnancy, being overweight, varicose veins, and certain medicines. They can also be caused by injury, infection, a blood clot, or medical problems affecting the heart, kidneys, liver, or thyroid.

Common causes

  • Prolonged standing or sitting.
  • High salt intake and fluid retention.
  • Pregnancy.
  • Medicines such as some blood pressure drugs, hormones, antidepressants, steroids, and NSAIDs.
  • Venous insufficiency or varicose veins.
  • Injury, infection, or an insect bite/sting.
  • More serious conditions like heart, kidney, or liver disease, or a blood clot.

When to get urgent help

Seek urgent care if the swelling is sudden, painful, only in one leg, or comes with redness, warmth, fever, chest pain, or shortness of breath, because those can point to a blood clot or another serious problem.

What helps

For mild swelling, elevating your legs, moving around regularly, reducing salt, and wearing compression stockings can help. If the swelling is new, persistent, or recurring, it should be checked by a clinician.

If you want, I can also turn this into a short forum-style post with a headline and quick bullet points.