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Swelling of One Foot Symptoms, Causes & Common Questions

An illustration of two feet. The foot on the left is light purple and larger than the foot on the right, which is a light peach-tone and shows no swelling. The left foot has a lighter shade of purple on the shin above the ankle.
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A swollen foot may be caused blood vessel blockage, lymphatic blockage, or trauma from an injury. Other causes of swelling in one foot include skin infections like cellulitis, or ankle arthritis which can also be the cause of one swollen ankle. Read below for more causes, related symptoms, and treatment options for a swollen foot.

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One swollen foot explained

Swelling of one foot can be a concerning symptom as it can likely interfere with everyday activities. It can be caused by a variety of ailments affecting the foot, including trauma or venous blockage such as by a blood clot. Fluid backup can also be caused by physical obstruction, such as a mass, in the surrounding area. It is important to seek care if you have swelling of only one foot with no apparent cause.

Common characteristics of swelling of one foot

If you're experiencing swelling of one foot, it can likely be described by:

What causes swelling in the feet?

Swelling of one foot may be caused by a blockage of blood vessels, a blockage in the lymphatic system, or trauma.

Blood vessel blockage

Blood can build up in a single leg, causing swelling of the foot. Blood flows into the leg through arterial circulation and out of the leg through venous circulation. Blockage of either type of blood vessel will cause swelling. Blocked veins cause blood to pool in the foot or leg and blocked arteries will cause severe tissue damage and mild swelling.

  • Venous thrombosis: This refers to a clot in the blood vessels that return blood to the heart after it has traveled to the tissues. Venous thrombi (or clots) usually only affect one leg at a time and are formed when there is damage to a blood vessel causing turbulent flow (e.g. not direct flow to the heart). Additionally, individuals with cancer may be predisposed to form clots as a side effect of their malignancy. Surgery and a sedentary lifestyle or a long period of sitting (e.g. plane or car rides) may also predispose an individual to form a clot. If clots are not treated properly, they can travel to the lungs and lead to death.
  • Peripheral artery disease: This is a disease in which the arteries that provide blood flow to the lower legs are gradually closed off by cholesterol or fats over time. Without proper blood flow, the leg may become cold and die, necessitating amputation (e.g. surgical removal). When peripheral artery disease causes blockage of the artery, the leg will become severely painful for a short period of time and then it will become cold compared to the opposite leg. If you suspect that you may have lost blood flow to your leg it is important to seek medical care immediately.
  • Compartment syndrome: This occurs when swelling of the muscle stops the flow of blood to the lower leg. Unlike peripheral artery disease, this can occur without any arterial blockage and is known to occur in young athletes, especially after long periods of physical exertion. Soccer players and long-distance runners may experience severe swelling of the muscles of their lower legs after a long period of intense running followed by severe pain and then numbness. The treatment for compartment syndrome is to decompress the leg with an emergent surgery known as a fasciotomy.

Lymphatic blockage

A lymphatic blockage, also known as lymphedema, is a chronic condition that can be caused by surgery that blocks the vessels that allow lymph to flow out of the legs (e.g. lymphatic vessels).

  • Surgery: Surgery for anywhere in the body requires a surgeon to separate or even destroy structures to gain access to the area that needs to be operated on. Surgery on the leg, abdomen, or pelvis can destroy or injure lymphatic vessels that are necessary to drain lymphatic fluid from the body. In some cases, removal or destruction of the lymphatic system is the goal. In surgery to remove cancers in the pelvis, a certain number of lymph nodes will be removed to ensure that cancer has not spread or to control any potential spread. Without those lymphatic structures, it can be difficult to drain lymphatic fluid from the body and lymphedema can result. Over time, lymphedema can cause hardening of the skin and a "woody" texture to the leg or affected foot.
  • Radiation treatment: Used for cancer, radiation can also damage many of the different lymphatic vessels and cause lymphedema. Radiation of the legs or pelvis for bladder, gynecological, or lower abdominal cancer can cause scars that restrict the flow of lymphatic fluid throughout the body and lead to lymphedema of the lower legs. There is no effective way to repair the lymphatic system if the damage spreads throughout the affected body part (e.g. leg, abdomen). However, physical activity can help move lymph and slow the progression of lymphedema.
  • Infection: Short-term infections do not cause lymphedema; however, long-term infections can. Infections that exist at a lower (e.g. subacute) level or that tend to exist within the lymphatic system can cause lymphedema if not treated in an expedient manner. Mycobacterium is a class of bacteria that is slow-growing and causes tuberculosis and leprosy among other infections. If left untreated, it can damage the lymphatic system and cause lymphedema.
  • Cancer: As it spreads throughout the body, cancer can damage the lymphatic vessels and lymph nodes and lead to incurable lymphedema. Even if the cancer is successfully treated, the effects of the damage to the lymphatic system may be irreversible and the leg may be swollen permanently.


Trauma may cause swelling of a foot or leg in the short-term. A sprain, fracture, or bruise can cause swelling of the entire foot for hours or even a day or so after the injury.

  • Sprain: A sprain involves anything from a partial tear to a complete tear of a ligament (e.g. a cord of connective tissue connecting muscle and bone). The severity of the sprain does not predict the severity of the lower leg or foot swelling. Your entire foot may be swollen and unable to bear weight for a mild sprain and you may have minimal swelling for a complete tear. Often a physical exam, X-rays, and whether or not you regain the ability to move your foot or extremity quickly determine the severity of the sprain. In all cases, rest, ice, compression, and elevation help decrease swelling and pain and you should seek medical evaluation.
  • Fracture: A mild fracture appears similar to a sprain. Swelling, inability to bear weight on the foot or move the foot are common symptoms. However, more severe fractures may result in obviously deformed or misaligned bones or joints. In those cases, it is important that the foot is reset in the proper position either in the emergency department or more commonly through a surgical procedure in which bones are fixed to each other to promote proper healing.

This list does not constitute medical advice and may not accurately represent what you have.

Skin infection of the foot

An infection of the skin of the foot is almost always either fungal or bacterial. A fungal infection of the foot is called tinea pedis, or athlete's foot. It is caused by different types of dermatophyte fungus and is commonly found in damp places such as showers or locker room floors. A bacterial infection anywhere on the skin is called cellulitis if it extends under the skin. It can develop after a break in the skin allows bacteria to enter and begin growing. These bacteria are most often either Streptococcus or Staphylococcus, which are found throughout the environment.

Most susceptible are diabetic patients, since high blood sugar interferes with healing and wounds can easily become chronic and/or deeply infected. Diagnosis is made through physical examination by a medical provider.

Treatment for either a fungal or bacterial infection involves keeping the skin dry and clean at all times. A fungal infection is treated with topical and/or oral antifungal medications, while a bacterial infection will be treated with topical and/or antibiotic medications.

Rarity: Uncommon

Top Symptoms: fever, foot pain, foot redness, warm red foot swelling, swollen ankle

Symptoms that always occur with skin infection of the foot: foot redness, foot pain, area of skin redness

Urgency: Primary care doctor

Septic arthritis

Septic arthritis is also called infectious arthritis. "Arthritis" simply means inflammation of a joint. In septic arthritis, the inflammation is caused by a bacterial, viral, or fungal infection. The most common agent is Staphylococcus aureus, or staph.

These agents reach the joints either from another infection in the body, or from a traumatic injury that contaminates the wounded joint.

Risk factors include existing joint disease or injury; a weakened immune system; and damaged skin. All of these things allow infectious agents to get a foothold.

Symptoms include severe pain in the affected joints, along with redness and swelling. The knees are most often affected but septic arthritis can occur in any joint.

The infection can damage cartilage and bone very quickly, so anyone with these symptoms should see a medical provider as soon as possible.

Diagnosis is made through a sample of the joint fluid; blood tests; and x-ray or CT scan of the joint.

Treatment involves draining the infected fluid from the joint, either with a needle or with surgery, followed by antibiotics.

Septic arthritis is also called infectious arthritis. "Arthritis" simply means inflammation of a joint. In septic arthritis, the inflammation is caused by a bacterial, viral, or fungal infection. The most common agent is Staphylococcus aureus, or staph.

These agents reach the joints either from another infection in the body, or from a traumatic injury that contaminates the wounded joint.

Risk factors include existing joint disease or injury; a weakened immune system; and damaged skin. All of these things allow infectious agents to get a foothold.

Symptoms include severe pain in the affected joints, along with redness and swelling. The knees are most often affected but septic arthritis can occur in any joint.

The infection can damage cartilage and bone very quickly, so anyone with these symptoms should see a medical provider as soon as possible.

Diagnosis is made through a sample of the joint fluid; blood tests; and x-ray or CT scan of the joint.

Treatment involves draining the infected fluid from the joint, either with a needle or with surgery, followed by antibiotics.

Rheumatoid arthritis

Rheumatoid arthritis is a chronic inflammatory disorder that affects the lining of the joints, causing them to become thickened and painful. It can also affect other parts of the body such as the heart, lungs, eyes, and circulatory system.

Rheumatoid arthritis is an autoimmune disease, which means the body's immune system turns against itself for unknown reasons.

Most at risk are women from ages 30-60. Other risk factors are family history, smoking, and obesity.

Early symptom include warm, swollen, stiff, painful joints, especially the fingers and toes; fatigue; and fever. Usually, the same joints on both sides of the body are affected.

If untreated, irreversible joint damage and deformity can occur, with other complications. Early diagnosis can allow preventive treatment to begin as soon as possible.

Diagnosis is made through physical examination; blood tests; and x-ray, CT scan, or MRI.

There is no cure for rheumatoid arthritis, but the disease can be managed to improve quality of life. Treatment includes nonsteroidal anti-inflammatory drugs; steroids; anti-rheumatic drugs; physical therapy; and sometimes surgery to repair the joints.

Nail infection (paronychia)

Paronychia is an infection of the skin of the fingers or toes, at the place where the skin folds down to meet the nail.

Acute, or sudden onset, paronychia is caused by the staphylococcus bacteria. The organism can gain entry if the nail is cracked, broken, bitten, or trimmed too closely.

Chronic, or ongoing, paronychia is caused by a fungus. Anyone whose work requires their hands to be wet much of the time is susceptible.

People with diabetes or a weakened immune system are more susceptible to nail infections.

Symptoms include sore, reddened, swollen skin around the nail, sometimes with pus collecting under the skin.

Diagnosis is made through physical examination and sometimes skin culture to identify the organism involved.

Treatment for acute paronychia involves having a medical provider clean the wounded nail and drain any infection, and sometimes provide a course of antibiotics.

Treatment for the chronic form involves keeping the skin dry and using an antifungal medication on the affected nail.

Rarity: Rare

Top Symptoms: spontaneous finger pain, fingernail pain, fingernail swelling

Urgency: Phone call or in-person visit


Gout is a form of arthritis that causes sudden pain, stiffness, and swelling in a joint. The big toe is often affected, but it can also happen in other joints. Sometimes, the joint gets hot and red. Gout is caused by uric acid crystals. Risk factors for gout include obesity, eating a lot of meat, drinking beer, age (older), sex (male), and family history.

You should see a healthcare professional to see if uric acid crystals have accumulated in the joint. Gout can be diagnosed based on symptoms, but it's also common to take a sample of joint fluid for testing. A physician can give you a prescription for anti-inflammatory medications and/ or pain medications. There are also medications to stop your body from making too much uric acid. Sometimes, a shot in the joint can help with symptoms also.

Rarity: Common

Top Symptoms: swollen toes

Urgency: Primary care doctor

Foot sprain

The bones of the ankle and foot are held together by ligaments, which are bands of tough tissue. An ankle sprain is a type of injury where one or more of the ligaments is stretched too far, causing tiny fibers in the ligaments to tear. In most cases, the ligament does not tear completely. A sprain is caused by the ligaments being stretched too far or tearing. This can happen when the foot rolls rolls, twists or turns too much.

Deep vein thrombosis

A deep vein thrombosis (DVT) occurs when a blood clot forms in a vein deep in the body, usually in the lower leg or thigh. DVT can cause swelling, pain, and redness in the affected leg. Some of the risk factors for developing DVT include obesity, pregnancy, cancer, surgery, and previous history of blood clots.

You should consider calling your primary care or urgent care provider. Deep vein thrombosis can be evaluated with a review of your symptoms, a physical exam, and an ultrasound. A blood test may also be performed. Once diagnosed, DVT can be treated with blood-thinning medication, which is usually taken for three months.

Rarity: Uncommon

Top Symptoms: fever, thigh pain, upper leg swelling, calf pain, butt pain

Urgency: Hospital emergency room

Broken foot (navicular bone fracture)

The navicular is one of the bones of the foot.

You should visit your primary care physician. An X-Ray may be helpful to confirm the diagnosis.

Rarity: Rare

Top Symptoms: difficulty walking, constant foot pain, pain in one foot, recent ankle injury, foot pain from overuse

Symptoms that always occur with broken foot (navicular bone fracture): pain in one foot, constant foot pain, recent ankle injury

Urgency: In-person visit

Broken ankle

An ankle fracture is a break in 1 or more ankle bones.

You should seek immediate medical care. The ankle will likely be splinted, but in severe cases, surgery may be necessary.

Rarity: Common

Top Symptoms: difficulty walking, constant ankle pain, swollen ankle, pain in one ankle, ankle pain from an injury

Symptoms that always occur with broken ankle: pain in one ankle, swollen ankle, ankle pain from an injury, constant ankle pain

Urgency: Hospital emergency room

Ankle arthritis

Arthritis simply means inflammation of the joints. Because the feet and ankles have many small joints and carry the weight of the body, they are often the first place that arthritis appears.

Ankle arthritis is caused by a breakdown in the protective cartilage at the end of each joint, so that the bones begin to wear against each other and the joint becomes stiff and painful. This breakdown may be due to simple wear and tear; an injury; or from rheumatoid arthritis, an autoimmune condition which causes the body to break down its own cartilage.

Symptoms include swelling, warmth, and redness in the joint, and pain with movement or with pressure on the joint.

Diagnosis is made through patient history, physical examination, and imaging such as x-rays, CT scan, or MRI.

There is no cure for arthritis, but treatment is important because the symptoms can be managed to prevent further damage, ease pain, and improve quality of life. Treatment involves physical therapy, pain-relieving medications, and sometimes surgery to help repair damaged joints.

Rarity: Uncommon

Top Symptoms: swollen ankle, swollen foot, joint stiffness, pain in one ankle, ankle stiffness

Urgency: Self-treatment

How to treat swelling in one foot or ankle

Treatment of foot or lower leg swelling is determined by the cause of the swelling. In cases of infection with an abscess, drainage of the abscess and antibiotics may be necessary. In the case of occluded blood vessels, the vessels may need to be opened up either through surgery or medications that dissolve the clot, and in cases of trauma, the bone or ligament may need time to heal.

Blocked blood vessels

A blood vessel that has been blocked by arteriosclerosis or a clot has to be opened up before the tissue suffocates and dies. The following may take place once you seek care in a hospital.

  • The clot may be dissolved, ensuring that it does not travel to your lungs
  • The blood vessel may be opened or bypassed: Or a limb that has died may need to be removed
  • Fasciotomy: A fasciotomy may be completed to alleviate pressure from compartment syndrome.

Sprain or fracture

A sprain or fracture that is mild can be treated at home, but if the pain is too intense or recovery does not occur within a week, medical treatment should be pursued.

  • Mild sprains: These should be treated with rest, ice, compression, and elevation as well as anti-inflammatory pain medications (NSAIDs).
  • Severe sprains or fractures: These should be evaluated by a medical professional and may need to be placed in some sort of brace to heal or may require surgery to realign the bones.


Lymphedema usually has no treatment but can be managed successfully through exercise and compression garments

When swelling of one foot is an emergency

You should seek help without delay if:

  • Sudden onset of severe pain or discomfort in the affected foot
  • Redness or warmth in the affected foot, especially if it is accompanied by fever or chills
  • You have lost sensation in your foot
  • You have lost your pulse or your foot has grown cold
  • You cannot bear weight on your foot
  • You have swelling that does not improve
  • You have shortness of breathchest pain, or difficulty breathing
  • Fainting or loss of consciousness

FAQs about swelling of one foot

What causes swelling in one foot?

Swelling in one foot is caused by fluid buildup in the foot. Fluid accumulation can take place through many mechanisms. The most common is inflammation following an infection or trauma to the tissues of the foot. When an infection in the foot occurs, the blood vessels of the foot dilate so that white blood cells and other immune cells can access the infected material. When trauma such as a sprain or fracture occurs, the tissues of the foot swell and become inflamed to clean up any blood from bruising and to make the foot sensitive or painful so that it is not used excessively in order to allow time for it to heal.

When is swelling in one foot dangerous?

Swelling in one foot is common, and by itself, it may not need evaluation. However, it should be evaluated urgently by a medical professional for a few reasons: if your foot has become cold in comparison to its partner, you have lost feeling, or you are unable to move your foot. You may have damage to the blood vessels that supply your foot or damage to the nerves that allow you to sense or move your foot. Damage to blood vessels can lead to tissue death and necessitate amputation whereas damage to the nerves in the foot can lead to a permanent inability to use the foot. In both cases, it is necessary to seek evaluation to preserve function and to possibly avoid life-threatening consequences of damage to the foot. Finally, swelling in the foot should be evaluated urgently in the setting of an inability to catch one's breath or pain in the calf as these may be signs of a clot in the leg.

When is foot swelling a sign of an infection?

Foot swelling is most commonly a sign of infection if it is accompanied by a rash or redness along the area where the foot is tender and if there is evidence of fever, chills, or pus emanating from a wound. In some people, these rashes can be signs of cellulitis or erysipelas which are both infections of the skin (albeit by different organisms). A wound that refuses to heal and produces pus or an abscess (a swollen, seemingly fluid-filled sac) are both signs of infection with bacteria that commonly cause skin infections. Often times, rashes or abscesses require medical treatment or drainage to begin healing.

How long does foot swelling from sprain take to disappear?

Foot swelling from a sprain can take variable amounts of time to disappear and can be affected by the degree of injury to the ligament and the treatments that are employed to help the ligament heal. Generally, minor sprains can be treated with the following: by resting and not bearing weight or even using crutches, using cryotherapy or chilling the ankle with ice, using compression or an elastic bandage early to minimize swelling, and elevating or raising the leg above the heart to limit swelling. Over-the-counter painkillers or non-steroidal anti-inflammatory drugs can limit both swelling and pain. Ankle splints can also keep the ankle from being injured as weight-bearing is slowly increased. It may take six to eight weeks to return to full capability following an injury with good care.

How should I treat foot swelling from a blow to the foot?

Swelling from a blow to the foot can usually be treated with at-home treatments described through the acronym R.I.C.E. "R" stands for rest which means that you should avoid placing weight on the foot. "I" stands for ice or cold, meaning the ankle should be chilled both to reduce swelling and to reduce pain. "C" stands for compression which also helps keep fluids from building up within the ankle. "E" stands for elevation specifically above the heart which reduces the ability of blood to pool in the limb. NSAIDs or non-steroidal anti-inflammatory medications are used to decrease swelling in the ankle. Once pain begins to increase, it is very important to resume activity and stretch the ankle as it will allow. Splints and braces are also very useful to stabilize the ankle and increase the ability to gradually increase strain on the ankle. Surgery for severe sprains may help improve the eventual ability of the ankle to bear weight.

Questions your doctor may ask about swelling of one foot

  • Where exactly is your foot swelling?
  • What is your body mass?
  • Do you have a history of high cholesterol?
  • Have you ever been diagnosed with diabetes?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

Hear what 7 others are saying
Once your story receives approval from our editors, it will exist on Buoy as a helpful resource for others who may experience something similar.
The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
Swaling in one foot top sidePosted January 15, 2022 by Z.
Swaling in my right side foot in top means in front side foot behind the fingers toper side swaling in one week.and also pain in thumb and fingers behind top side
Just the right ankle is swellingPosted November 22, 2021 by C.
Ever since I got over Covid-19 over a year ago, I have had trouble with only my right foot swelling. It doesn’t matter if I am standing or sitting with my foot up. I can’t stop the swelling. It does go down when I am asleep at night, but just as soon as I get out of bed within 10 minutes the swelling starts. Some days it’s just the ankle, but other days it swells up to my knee and even the bottom of my foot. I have talked to a few doctors, but all I get told is it’s just a side effect from COVID-19. So I guess it’s something I will have to learn to live with.
Swollen anklePosted November 10, 2021 by H.
Husband has very swollen ankle. Doctor checked everything out and supposedly there are no problems. However it’s very hard for him to put a shoe or boot on unless he gets an extra large size. We live on a farm and he needs to wear boots in winter since we are in very cold climate. However he cannot find any boots that fit him. He won’t wear a compression socks because he said they are impossible to get on. He is fairly active since we live on a farm, but he is 80 years old. What else can be done to try and help the swelling? Isn’t there any machine that can massage your leg and try to get some of the swelling out that maybe you can use on a daily basis. Thanks for any information or help
Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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