Corticosteroids: Certain steroid medications can affect fluid balance and contribute to swelling.
Hormonal medications: Some estrogen-containing medications and other hormonal treatments may contribute to fluid retention.
Certain diabetes medications: Thiazolidinediones, such as pioglitazone, can cause fluid retention and may worsen heart failure in susceptible individuals.
If swelling begins after starting a new medication or changing a dose, discuss it with your healthcare provider.
Do not stop prescribed medication without medical advice.
10. Blood Clots in the Leg
A blood clot in a deep vein, known as deep vein thrombosis (DVT), is a potentially serious cause of leg swelling.
DVT commonly develops in the deep veins of the lower leg or thigh.
A clot can obstruct blood flow and cause swelling, pain, warmth, and changes in skin color.
Unlike many other causes of edema, DVT often affects only one leg.
Possible warning signs include:
-
Sudden swelling in one leg.
-
Pain or tenderness in the calf.
-
Warmth in the affected area.
-
Redness or discoloration.
-
A feeling of tightness in the leg.
Not everyone with DVT experiences all these symptoms.
The greatest concern is that part of the clot may break away and travel to the lungs, causing a pulmonary embolism.
Symptoms of pulmonary embolism include sudden shortness of breath, chest pain that may worsen with breathing, coughing up blood, rapid heartbeat, or fainting.
A suspected DVT requires urgent medical evaluation. If symptoms suggest pulmonary embolism, seek emergency medical care immediately.
Chapter 3: One Swollen Foot or Both? Why the Difference Matters
The location and pattern of swelling can provide useful clues about its possible cause.
One important distinction is whether both feet are swollen or only one.
Although this is not enough to establish a diagnosis, it can help healthcare professionals decide which conditions need to be investigated.
When both feet are swollen
Swelling affecting both feet and ankles may be associated with:
-
Heart failure.
-
Kidney disease.
-
Advanced liver disease.
-
Chronic venous insufficiency.
-
Medication side effects.
-
Pregnancy.
-
Prolonged standing or sitting.
The swelling may develop gradually and become more noticeable toward the end of the day.
Some people also experience swelling in the lower legs or abdomen.
If both feet are persistently swollen without an obvious explanation, a medical assessment is recommended.
When only one foot or leg is swollen
Swelling affecting only one leg deserves particular attention.
Possible causes include:
-
Deep vein thrombosis.
-
Cellulitis or another skin infection.
-
Injury or trauma.
-
A joint or tendon problem.
-
Lymphatic obstruction.
-
Localized inflammation.
Sudden swelling in one leg, especially when accompanied by pain, warmth, or redness, should be assessed urgently to rule out a blood clot.
A person should not assume that one-sided swelling is simply caused by standing too long.
When swelling comes and goes
Some people experience swelling that appears during the day and improves overnight.
This pattern can occur with dependent edema, which develops when gravity encourages fluid to accumulate in the lower parts of the body.
It may also occur with chronic venous insufficiency.
However, improvement after resting does not completely rule out an underlying medical condition.
The frequency, severity, and accompanying symptoms all matter.
Chapter 4: Seven Warning Signs That Swollen Feet Should Not Be Ignored
Swollen feet are often uncomfortable, but certain accompanying symptoms may indicate a more serious medical problem.
Recognizing these warning signs can help you seek care at the right time.
1. Sudden swelling in one leg
If one leg suddenly becomes swollen, painful, warm, or discolored, deep vein thrombosis should be considered.
DVT can lead to pulmonary embolism, a life-threatening complication.
Seek urgent medical evaluation rather than waiting for the swelling to disappear.
2. Shortness of breath
Swollen feet combined with shortness of breath may indicate heart failure or another serious heart or lung condition.
If breathing becomes suddenly difficult, especially with chest pain, fainting, or coughing up blood, seek emergency medical care.
3. Rapid weight gain
A sudden increase in body weight over a few days may sometimes reflect fluid retention rather than an increase in body fat.
This can be particularly important for people with heart failure, kidney disease, or cirrhosis.
People with diagnosed heart failure should follow their clinician's instructions about daily weight monitoring and when to report changes.
4. Yellowing of the eyes or skin
Jaundice may indicate a problem involving the liver, bile ducts, or blood.
When it appears alongside swollen feet or abdominal swelling, prompt medical evaluation is necessary.
5. Reduced urine output
A noticeable decrease in urine output, particularly when accompanied by swelling, may indicate impaired kidney function or significant fluid imbalance.
Sudden inability to urinate or a marked reduction in urine output should be assessed urgently.
6. Fever, redness, and warmth
Swollen skin that becomes red, hot, and painful may indicate cellulitis, a bacterial skin infection.
Fever, chills, or rapidly spreading redness can signal a more serious infection.
Medical treatment may be necessary, often involving antibiotics.
7. Skin breakdown or open sores
Long-term swelling can stretch and damage the skin.
People with chronic venous insufficiency may develop ulcers around the ankles.
Open wounds can become infected and may heal slowly, particularly in people with diabetes or poor circulation.
Persistent sores, drainage, increasing pain, or spreading redness should be examined by a healthcare professional.
Chapter 5: How Doctors Determine the Cause of Swollen Feet
Because many conditions can produce similar symptoms, doctors generally use a combination of medical history, physical examination, and diagnostic tests.
The goal is not simply to confirm that swelling exists, but to identify why fluid is accumulating.
1. Medical history
A healthcare professional may ask:
-
When did the swelling begin?
-
Does it affect one foot or both?
-
Is it worse in the morning or evening?
-
Does it improve after elevating the legs?
-
Is there pain, redness, or warmth?
-
Have you recently started a new medication?
-
Do you have diabetes, high blood pressure, or heart disease?
-
Have you recently traveled for a long period?
-
Have you experienced shortness of breath or chest discomfort?
These details help narrow down possible causes.
2. Physical examination
The doctor may examine the feet, ankles, calves, and abdomen.