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Damage to lymph nodes during cancer surgery.
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Radiation treatment affecting lymphatic vessels.
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Certain infections.
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Congenital abnormalities of the lymphatic system.
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Other conditions that interfere with lymphatic drainage.
In some cases, no clear cause is identified.
Lymphedema requires a different approach from ordinary fluid retention. Treatment may include specialized compression garments, skin care, exercise, and manual lymphatic drainage performed by appropriately trained professionals.
Protecting the skin is especially important because chronic swelling can increase the risk of skin infections. Even small cuts, cracks, or insect bites should be cleaned and monitored carefully.
If one foot or leg gradually becomes larger than the other, particularly after lymph-node surgery or cancer treatment, medical assessment can help identify the cause and guide treatment.
9. Medication Side Effects Can Cause Swollen Legs
Sometimes, the explanation for swollen ankles is not a new disease but a medication.
Several commonly prescribed medicines can contribute to fluid retention or alter circulation. This possibility is easy to overlook because swelling may develop gradually after a medication is started or its dose is increased.
Examples include:
Certain blood pressure medicines: Calcium-channel blockers, such as amlodipine, can cause swelling around the ankles in some people. This occurs partly because of changes in pressure within small blood vessels and does not necessarily mean that the heart or kidneys are failing.
Nonsteroidal anti-inflammatory drugs: Medicines such as ibuprofen and naproxen can cause the body to retain sodium and water in some circumstances. They may also worsen kidney function in susceptible individuals.
Corticosteroids: Some steroid medicines can contribute to fluid retention, depending on the medication, dose, and duration of use.
Hormonal medications: Certain estrogen-containing treatments and other hormonal medicines may contribute to swelling or increase the risk of blood clots, depending on the specific medication and individual risk factors.
Some diabetes medicines: Certain drugs, including thiazolidinediones, can cause fluid retention and may worsen heart failure in susceptible people.
Other medications may also contribute, depending on the circumstances.
If swelling begins after starting a new medicine, make a note of when the symptoms appeared and discuss the timing with your healthcare professional or pharmacist.
Do not stop a prescribed medicine abruptly or change the dose on your own. A clinician may be able to adjust the treatment, change the medication, or investigate another cause.
Medication-related swelling should not automatically be assumed to be harmless. New or rapidly worsening swelling still requires appropriate assessment, particularly if breathing difficulties or other warning signs develop.
10. Pregnancy and Swollen Legs
Mild swelling in the feet and ankles is common during pregnancy, particularly in the later months.
Several normal physiological changes contribute to this. The body retains more fluid, the growing uterus places pressure on veins that return blood from the lower body, and hormonal changes affect circulation.
Swelling may be more noticeable after prolonged standing, during hot weather, or at the end of the day. Both feet and ankles are often affected.
However, pregnancy also increases the risk of developing blood clots. New swelling that affects one leg more than the other, especially when accompanied by pain, warmth, or redness, should be assessed urgently.
There is another important warning sign: sudden or rapidly increasing swelling, particularly when accompanied by a severe headache, visual disturbances, pain in the upper abdomen, or high blood pressure.
These symptoms may indicate preeclampsia, a potentially serious pregnancy complication that can affect the mother's organs and the baby's health.
Preeclampsia can occur after 20 weeks of pregnancy and may also develop after delivery. Swelling alone does not diagnose the condition, but concerning symptoms should never be ignored.
Seek immediate medical advice if you develop warning signs of preeclampsia. Severe symptoms, seizures, chest pain, or significant breathing difficulty require emergency care.
For ordinary pregnancy-related swelling, a maternity care professional may recommend resting with the legs elevated, avoiding prolonged standing, moving regularly, and considering appropriately fitted compression garments.
Pregnant people should consult their maternity care team before using medicines, herbal products, or diuretics for swelling.
11. An Injury or Infection May Be Responsible
Not every swollen leg is caused by fluid retention throughout the body. Local injuries and infections can produce swelling in a specific area.
Injuries
A sprained ankle, muscle strain, fracture, or direct blow can damage tissues and cause inflammation. Fluid then accumulates around the injured area, producing swelling, tenderness, and sometimes bruising.
The location and severity of the symptoms may provide clues, but a fracture or other significant injury cannot always be ruled out based on appearance alone.
Seek medical assessment if you cannot bear weight, have severe pain, notice a deformity, or experience substantial swelling after an injury.
Cellulitis
Cellulitis is a bacterial infection of the skin and tissues beneath it. It commonly causes a painful, warm, swollen area of skin that may look red or darker than the surrounding skin, depending on the person's skin tone.
The affected area may expand, and the person may develop fever, chills, or a general feeling of illness.
Cellulitis can become serious if treatment is delayed. Prompt medical evaluation is important because antibiotics are often needed.
People with diabetes, chronic edema, or damaged skin may be particularly vulnerable to complications.
Other inflammatory conditions
Joint inflammation, gout, and certain skin conditions can also cause localized swelling around the ankle or foot.
The key is to look at the entire pattern of symptoms. Swelling accompanied by significant pain, fever, warmth, spreading redness, or an inability to walk should not be dismissed as ordinary tiredness.
Do not massage a suddenly swollen, painful leg until a blood clot has been considered and medical advice has been obtained.
12. Sitting for Too Long Can Contribute to Leg Swelling
Modern lifestyles often involve long periods of sitting, whether at a desk, during a long-distance flight, or while traveling by car or bus.
When the leg muscles remain inactive, they do not help push blood back toward the heart as effectively. Blood can pool in the lower legs, increasing pressure in the veins and encouraging fluid to accumulate in surrounding tissues.
This can lead to temporary swelling around the ankles and feet.