13 Causes of Swollen Feet

You've got to hand it to your feet. They might just be the hardest-working part of your body.

They take a beating every day by supporting your body weight and letting you walk, run, jump, and stand. The 26 bones and more than 100 muscles, tendons, and ligaments in each foot and ankle work as a team to carry you wherever you go each day.

All of that foot action adds to a lot of wear and tear. So, it isn't surprising that one of people's biggest complaints is swollen feet. But swollen feet also have other serious causes, some of which may be red flags for other health issues.

Here's what you need to know about 13 causes of swollen feet and what to do about them.

What Happens When Feet Swell

So, what exactly happens when feet swell? Due to standing, inactivity, injury, or some other cause, fluid builds up in your feet, ankles, and legs. And gravity helps that fluid build-up, Dyane Tower, DPM, director of clinical affairs at the American Podiatric Medical Association (APMA), told Health.

Standing for Hours at a Time

Anyone who works on their feet may feel like their shoes are too tight at the end of the day. Edema is common in people who have to stand for long periods at work.

With edema, blood gathers in the veins of your legs because of gravity. Fluid from the blood begins to pool into the tissues in your legs, feet, and ankles, causing swelling. You may notice that your shoes feel tighter than normal.

While annoying, that kind of end-of-the-day swelling usually does not indicate a serious problem. It should go away once you've rested your feet.

"There are no hard and fast guidelines. But if you're on your feet all day long, it's reasonable to sit five minutes every hour or put your legs up," Jason Johanning, MD, professor of vascular surgery at the University of Nebraska Medical Center, told Health.

Compression stockings may also be helpful if the swelling persists or you can't take breaks from standing or walking.

"Compression stockings work the same way as walking and add a bit of pumping action to keep the blood flowing a little faster," Roy Silverstein, MD, chair of medicine at the Medical College of Wisconsin, told Health.

Salt

The sodium that partly makes up salt, also known as sodium chloride, is one of the biggest dietary culprits of water retention. The American Heart Association (AHA) recommends that adults consume no more than 2,300 milligrams, about one teaspoon, of sodium daily.

Sodium can hide among a list of ingredients in processed and take-out foods, including:

• Cold cuts
• Snacks like chips, popcorn, and crackers)
• Pizza
• Soups
• Bread
• Tacos and burritos
• Cheese
• Eggs

Try to limit your intake of those foods, swapping for sodium-free or low-sodium items. You can monitor the sodium content in food by looking at the nutrition labels.

Pregnancy

For many people, swollen feet are an inevitable part of pregnancy. Foot swelling can make pregnancy uncomfortable and worsens as the due date approaches.

"As the [fetus] grows, it presses on the pelvic veins, and you get a little bit of compromised circulation," Jill Rabin, MD, professor of obstetrics and gynecology at the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, told Health.

"If you have a big belly from pregnancy, lying on your back causes the blood vessels to compress," explained Dr. Rabin. "That makes it more difficult for the circulation to get back to the heart and will sometimes cause some of the fluid in the veins to seep out."

Usually, the swelling is nothing to worry about. But if it comes on rapidly, especially in your hands and face, call a healthcare provider. Rapid swelling could be a sign of preeclampsia, which leads to dangerous, rapid-onset high blood pressure.

To ease swollen feet due to pregnancy, try some of the following techniques:

• Drink eight to 10 glasses of fluids daily.
• Don't drink caffeine or eat salty foods.
• Rest and elevate your feet.
• Ask a healthcare provider about support hose or compression socks.

Obesity

Obesity is an excess accumulation of body fat, which may cause health concerns. Body mass index (BMI) determines whether a person has obesity. For instance, a person with a BMI over 30 is considered obese.

A person with a BMI exceeding 50 may develop lower extremity swelling, per an article published in 2015 in Plastic and Reconstructive Surgery Global Open. According to the researchers, once your BMI reaches 50, weight loss may not reverse the swelling. Therefore, discussing treatment for foot swelling with a healthcare provider before reaching a BMI of 50 is important. 

Injury

Maybe you sprained your ankle during a gym workout, had a stress fracture of the leg or toe, or had surgery on your leg, ankle, or foot. Injuries like those may cause swelling in and around your feet.

"The body's response [to an acute injury] is inflammation," explained Dr. Tower. "The blood goes down to that area of the [foot] and brings cells and fluid." Ultimately, the cells and fluid can make your foot seem extra large.

If you do not have any symptoms of a serious injury, it's probably safe to treat the injury at home—at least at first. For example, use the RICE method, which relieves pain and inflammation and speeds healing, which includes:

• Rest: Limit activities using the injured area for at least a day or two. Try to avoid putting weight on or using the injured joint or limb.
• Ice: Apply an ice pack to the injured area for 20 minutes, four to eight times a day. Do not apply ice directly to the skin of an injured area. Instead, use a thin cloth to protect the skin. Also, do not apply ice directly to an open wound or surgical incision. 
• Compression: Keep pressure on the injured area to help reduce swelling. An elastic bandage works well, but do not wrap it so tightly that it cuts off the circulation.
• Elevation: Keep the injured body part elevated on a pillow above the level of the heart to help decrease swelling.

Also, do not use heat immediately after an injury. Heat tends to increase internal bleeding or swelling. Heat can be used later to relieve muscle tension and promote relaxation. If pain or other symptoms persist or worsen, check with a healthcare provider.

Premenstrual Syndrome (PMS)

Some people feel bloated during the week leading up to their periods. That waterlogged feeling is the normal result of sodium and water retention after ovulation, according to a study published in 2015 in the International Journal of Women's Health.  

That period after ovulation and before your period is when premenstrual syndrome (PMS) symptoms begin. In addition to bloating, swollen feet are another possible symptom of PMS. The researchers found that 65% of women studied experienced swelling during the premenstrual stage of their menstrual cycles.

"You can feel a little puffier or swollen for sure," Britt Marcussen, MD, clinical associate professor at the University of Iowa, told Health. "It's noticeable in the legs and feet, where it tends to pool because of gravity."

Medication

Certain medications have side effects of swelling in the lower extremities. For example, heart medications, known as vasodilators, help open up the blood vessels to make blood flow more freely. That increases the risk of leakage from the blood vessels to the surrounding tissue, causing swelling.

Also, calcium channel blockers can cause leakage from the blood vessels into the tissue. That leakage may cause swelling in the feet.

Other drugs that can cause swollen feet may include chemotherapy drugs, like Taxotere (docetaxel).

Infection

Skin infections cause particularly painful swollen feet. For instance, cellulitis is a bacterial infection of the skin that causes pain, swelling, and redness in the affected area.

"The swelling is usually associated with red, hot, sore skin," explained Dr. Marcussen.

People with diabetes are more prone to infections. Diabetes can cause peripheral vascular issues, which decreases a person's ability to heal cuts, sores, or infections. Diabetes also may cause peripheral neuropathy, which decreases the person's ability to feel a cut, sore, injury, or infection. 

If untreated, the wound can become infected, causing the feet to swell up. People with diabetes should have a yearly foot exam to prevent infections from developing.

Ensure all open sores and cuts are clean and covered with a bandage to prevent infection. Antibiotics usually clear up bacterial infections, whereas antifungal medications can treat fungal infections.

Lymphedema

Lymphedema is a kind of swelling. Lymph is a fluid that carries infection-fighting white blood cells to different body parts. Clusters of lymph nodes throughout your body control the travel of that fluid.

But if your lymph nodes become damaged or removed, say, during surgery for cancer, lymph won't drain properly, causing lymphedema. Lymphedema may also be idiopathic, meaning that there's no underlying cause.

Generally, swelling in the feet happens when the pelvic lymph nodes, which control lymph movement in your legs and feet, become injured or removed. 

"The lymphatic vessels are very thin and pliable. So, when you operate in the groin area, even with meticulous surgical care, they can be injured and can create an obstruction blocking the return of the lymphatic fluid," explained Dr. Johanning.

Occasionally, lymphedema is an inherited condition. Other times, cancer or infection causes lymphedema. If you suspect any of those conditions are causing your swollen feet, check in with a healthcare provider. But in the meantime, wearing compression stockings and moving around as much as possible can help.

"The muscles pump fluid out of the lymph channels," said Dr. Marcussen. "If you're up and around and moving a lot more, that can help alleviate [the problem]."

Heart Failure

Heart failure is when your heart isn't pumping enough blood. With heart failure, blood will back up in the veins, leading to fluid build-up. Swollen feet are one of the common signs of heart failure.

Usually, swelling in the feet points to right-sided heart failure. You may also experience other symptoms, such as:

• Nausea
• Weight gain
• Abdominal pain
• Swelling in your neck, legs, or abdomen

If swelling lasts long enough, you may also get pitting. Pitting is when the skin stays indented after you put pressure on it.

"If this and shortness of breath dramatically worsen, and you gain more than five pounds in a day, this should be concerning," explained Dr. Marcussen.

Blood Clots

After sitting for a long time without moving, your legs can develop swelling and pain in your leg. Those may be symptoms of a blood clot, known as deep vein thrombosis.

"The swelling is caused by the presence of the clot," explained Dr. Silverstein. "The clot causes pressure to increase behind the area of obstruction, and that increased pressure pushes the fluids in the blood out of the veins into the tissues."

While anyone who sits for long periods can develop a blood clot, certain factors or conditions can boost your risk, like:

• Pregnancy
• Smoking
• Heart disease
• Stroke
• High blood pressure
• Kidney problems
• A previous blood clot
• Cancer
• Birth control pills

Though a blood clot that causes foot swelling doesn't always have other symptoms, you'll typically feel pain in your leg.

"The most common presentation is significant pain and discomfort in the calf region with associated swelling of that limb," noted Dr. Johanning.

If caught in time, a healthcare provider can treat blood clots. But often, it isn't, and the blood clot can break off and travel to the lungs. In the lungs, a blood clot can cut off the oxygen supply, which may become lethal.

If those symptoms strike without explanation, notify a healthcare provider immediately, or head for the emergency room.

You can prevent blood clots by staying active and taking breaks to move around if you're sitting for long periods.

Kidney Failure

Your kidneys are responsible for balancing fluids in your body and moving fluid you don't need out of your system. So, you might end up with swollen feet when one or both aren't functioning properly. If your body is retaining extra salt, producing more fluid, your feet may puff up.

"Normally, people [with foot swelling] go home and put their feet up, and the body reabsorbs that little bit of extra fluid, and the kidneys just get rid of it," explained Dr. Marcussen. "[With] kidney problems, your body has trouble getting rid of that fluid, then that swelling is more marked and more dramatic. A lot of people have swelling other places, too, like their hands and face."

Medications, like diuretics, can help with kidney problems. Diuretics help dump the kidney fluid, which may help alleviate swelling in the feet.

Liver Disease

Cirrhosis of the liver happens if the liver develops permanent scarring from disease or damage. Scarring interferes with blood flow through the liver, which causes portal hypertension.

Portal hypertension is high blood pressure in the veins that goes into the liver, causing swelling in the legs, feet, and abdomen. Other signs of cirrhosis include:

• Feeling tired
• Unintentional weight loss
• Bloating
• Bleeding and bruising easily
• Nausea and vomiting
• Having yellow-tinted skin and eyes

Healthcare providers usually focus on treating the disease that causes cirrhosis. So, treatments vary, depending on the cause. Medications, weight loss, or recommendations to stop drinking alcohol may help. Also, diuretics and lifestyle measures like limiting salt intake can help with foot swelling.

A Quick Review

There are several different causes of swollen feet. You may just need to give them a break after a long day. Or swollen feet may be a sign of a serious health condition. Discuss your symptoms with a healthcare provider to determine the best course of treatment.