Foot Swelling: Why Your Feet Are Swollen

Swelling in both feet vs one foot

The most useful first question is whether one foot or both are swollen.

Common causes of swollen feet

Gravity and lifestyle

Long periods standing or sitting let fluid pool in the feet. Long flights and car trips, hot weather, a salty diet and being overweight all add to it. This swelling is soft, affects both feet, and settles overnight.

Pregnancy

Swelling of the feet and ankles affects most pregnant women, especially in the third trimester and in hot weather. It is caused by fluid retention and pressure from the womb on leg veins. Sudden swelling of the face and hands with headache or vision changes can be a sign of preeclampsia.

Vein problems

Chronic venous insufficiency occurs when leg vein valves fail and blood pools. It causes ankle and foot swelling worse at day's end, aching, varicose veins and, over time, brown discoloration and skin changes around the ankles.

Medicines

Calcium channel blockers (especially amlodipine and nifedipine), NSAIDs, steroids, estrogen, pioglitazone, gabapentin and pregabalin commonly cause foot swelling.

Injury

A sprained ankle, broken bone in the foot (including stress fractures in runners) or tendon injury causes swelling, bruising and pain. See ankle sprain.

Medical causes

• Deep vein thrombosis: a clot in a leg vein causes one-sided swelling, calf pain, warmth and redness. Risk rises after surgery, long travel, cancer, pregnancy and with birth control pills.
• Cellulitis: bacterial skin infection, often entering through cracks from athlete's foot, causes a red, hot, tender, swollen foot.
• Gout: sudden, intensely painful swelling and redness, usually of the big toe joint, often starting at night.
• Heart failure: swelling of both feet and ankles with breathlessness and tiredness.
• Kidney disease: swelling of the feet and around the eyes, foamy urine.
• Liver disease: swelling of the feet and belly, yellow skin.
• Lymphedema: firm swelling that includes the toes ("squared-off" toes), after lymph node surgery, radiation or infection, or present from birth.
• Charcot foot: in people with diabetic nerve damage, bones in the foot weaken and collapse, causing a warm, swollen, often painless foot. It needs urgent offloading to prevent deformity.
• Arthritis: rheumatoid arthritis, psoriatic arthritis and reactive arthritis can swell the joints of the feet and toes ("sausage toes").
• Underactive thyroid and lipedema (symmetrical fat buildup that spares the feet).

How doctors find the cause

A doctor will ask whether one or both feet swell, when it started, what makes it better or worse, about breathlessness, medicines, travel, injury and pregnancy. They will check for pitting, warmth, redness, tenderness, pulses, skin changes and varicose veins, and listen to your heart and lungs.

Tests may include:

• blood tests: kidney and liver function, albumin, thyroid, blood count, BNP for heart failure, uric acid for gout
• urine test for protein
• D-dimer and Doppler ultrasound if a clot is possible
• X-ray for injury or Charcot foot
• echocardiogram if heart failure is suspected

How to reduce swollen feet

• Raise your feet above the level of your heart for 20 to 30 minutes, 3 or 4 times a day.
• Keep moving: walk regularly, and flex and point your feet often when sitting or traveling.
• Wear compression socks (graduated, 15 to 20 mmHg for mild swelling). Check with a doctor first if you have diabetes, numb feet or poor circulation.
• Reduce salt in your diet.
• Drink enough water. Dehydration makes the body hold on to fluid.
• Wear comfortable, adjustable shoes.
• Lose excess weight.
• Review medicines with your doctor. Do not stop prescribed medicines on your own.
• For injuries: rest, ice wrapped in a cloth for 15 to 20 minutes at a time, compression and elevation in the first few days.

Diuretics (water pills) help when swelling comes from heart, kidney or liver disease, but they do not fix swelling from veins or standing and can cause dehydration.

Frequently asked questions

What causes swollen feet?

The most common causes are standing or sitting for long periods, heat, pregnancy, weak leg veins and medicines like amlodipine. Injuries, gout and infection cause swelling of one foot. Heart, kidney and liver disease can cause swelling of both feet along with other symptoms.

Why is only one of my feet swollen?

One-sided swelling usually has a local cause: a sprain or fracture, gout, cellulitis, an insect bite, or a blood clot in the leg. A swollen, painful, warm calf or foot needs same-day assessment to rule out a deep vein thrombosis.

When should I worry about swollen feet?

Get emergency help if swollen feet come with chest pain or breathlessness. See a doctor promptly for sudden swelling of one foot, redness and fever, swelling in pregnancy with headache, or swelling that keeps increasing over weeks.

How can I reduce swelling in my feet fast?

Lie down and raise your feet above your heart, move your ankles, and wear compression socks. Reduce salt and keep active. For an injury, use rest, ice, compression and elevation. If swelling does not improve or is one-sided and painful, see a doctor.

Can heart problems cause swollen feet?

Yes. In heart failure, the heart cannot pump blood effectively, so fluid backs up into the legs and feet. It usually affects both feet, leaves a dent when pressed, and comes with breathlessness and tiredness, especially when lying flat.