Have you noticed lately that your socks are tight and your pants feel snug? Your legs swell for two main reasons:

Fluid buildup (edema): It happens when the tissues or blood vessels in your legs hold more fluid than they should. This can happen if you simply spend a long day on your feet or sit for too long. But it may also be a sign that you’re overweight or don’t get enough exercise, or of more serious medical conditions.
Inflammation: It happens when the tissues in your legs get irritated and swollen. It’s a natural response if you break a bone or tear a tendon or ligament, but it also may be a sign of a more serious inflammatory illness, like arthritis.
Things That Cause Fluid Buildup

Several things can lead to extra fluid, or edema, in one leg, or both:

Congestive heart failure: This happens when your heart is too weak to pump all the blood your body needs. It leads to fluid buildup, especially in your legs. Other symptoms of congestive heart failure:

Shortness of breath or trouble breathing
Tiredness
Cough
Learn more about heart failure symptoms.

Vein Issues

Deep vein thrombosis (DVT) and thrombophlebitis: If you have DVT, it means there’s a blood clot in a vein in your leg. It could break off and travel to your lung. When that happens, it’s called a pulmonary embolism, and it can be life-threatening.


In thrombophlebitis, also called superficial thrombophlebitis, clots form closer to the surface of the skin and aren’t likely to break off.

One of the first symptoms of DVT or thrombophlebitis is one swollen leg (especially the calf), as blood pools in the area. Check with your doctor right away if you have swelling in one leg or any of these other symptoms:

Leg pain, tenderness, or cramping
Skin that’s tinged red or blue
Skin that feels warm
Learn more about blood clots in veins.

Varicose veins and chronic venous insufficiency: You get these conditions when the valves inside your leg veins don’t keep the blood flowing up toward your heart. Instead, it backs up and collects in pools, causing bluish clusters of varicose veins on your skin. Sometimes, they can make your legs swell.


Some other symptoms might include:

Pain after sitting or standing for a long time
Changes in skin color — you might see clumps of red or purple veins, or the skin on your lower legs might look brown
Dry, irritated, cracked skin
Sores
Achy legs
Learn more about symptoms of varicose veins.

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Kidney Problems

Long-term kidney disease happens when your kidneys don’t work the way they should. Instead of filtering water and waste material from your blood, fluid gathers in your body, which causes swelling in your arms and legs.

You may also notice symptoms like these:

Fatigue
Shortness of breath
Nausea
Too much thirst
Bruising and bleeding
Acute kidney failure — when your kidneys suddenly stop working — can also cause swollen legs, ankles, and feet. But it usually happens when you’re hospitalized with other problems. Learn more about acute kidney failure symptoms and causes.

Medications

Sometimes, swelling can be an unwelcome side effect of prescription drugs. The medications most likely to cause swollen legs include:

Heart medicines called calcium channel blockers are often to blame:
Amlodipine (Norvasc)
Nifedipine (Adalat CC, Afeditab CR, Nifediac CC, Nifedical XL, Procardia)
Nonsteroidal anti-inflammatory drugs (NSAIDs), like:
Aspirin
Ibuprofen
Naproxen
Celecoxib (Celebrex)
Certain diabetes drugs, including metformin
Hormone medications containing estrogen or progesterone
Some antidepressants

Call your doctor if you take any of these drugs and get swollen lower limbs. Learn more about common medication side effects.

Pregnancy

By the third trimester, your growing baby puts pressure on the veins in your legs. This slows the circulation of your blood and causes fluid to build up. The result: mild swelling.

If you notice these other symptoms as well, let your doctor know because it might mean you have a serious condition called preeclampsia:

Severe swelling, especially around your eyes
Bad headache
Vision changes, like blurriness or sensitivity to light
If, during the last trimester or soon after delivery, you have swollen legs and shortness of breath, talk to your doctor about a condition called peripartum cardiomyopathy, a type of heart failure related to pregnancy. Learn more about swelling and other discomforts during pregnancy.

Things That Cause Inflammation

If fluid buildup isn’t to blame for your swollen legs, it could be inflammation. Common causes include:

Arthritis and Other Joint Problems

Several diseases and conditions can make your legs swell:

Gout: A sudden painful attack caused by uric acid crystals in your joints that usually follows drinking heavily or eating rich foods. Learn more about the symptoms of gout.
Knee bursitis: Inflammation in a bursa, a fluid-filled sac that acts as a cushion between bone and muscle, skin, or tendon. Learn how to treat knee bursitis.
Osteoarthritis: The wear and tear type that erodes cartilage. Learn more about osteoarthritis symptoms.
Rheumatoid arthritis: A disease where your immune system attacks tissues in your joints. Learn more about rheumatoid arthritis.
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Injuries — Strains, Sprains, and Broken Bones

If you twist your ankle or break a bone, you’ll likely get some swelling. It’s your body’s natural reaction to the injury. It moves fluid and white blood cells into the area and releases chemicals that help you heal.

Some of the most common injuries are:

Achilles tendon rupture: This is your body’s largest tendon. It connects your calf muscles to your heel bone. It’s what helps you walk, run, and jump. If it tears, you might hear a pop then feel a sharp pain in the back of your ankle and lower leg. You probably won’t be able to walk. Learn more about Achilles tendon injuries.

Anterior cruciate ligament (ACL) tear: Your ACL runs diagonally across the front of your knee and holds the bones of your lower leg in place. When it tears, you’ll hear a pop and your knee may give out. It’ll also be painful and swollen. Learn more about ACL injuries.

Cellulitis: This serious infection happens when bacteria like streptococcus and staphylococcus get in through a crack in your skin. It’s most common in your lower leg. Other symptoms include:

A red area of skin that gets bigger
Tenderness
Pain
Warmth
Fever
Red spots
Blisters
Dimpled skin
Cellulitis can spread through your body quickly. Go to the ER if you have:

A fever
A red, swollen, tender rash that changes rapidly
See your doctor as soon as you can (the same day is best) if you have:

A swollen, red, tender, expanding rash but no fever.
Learn more about cellulitis symptoms and causes.

Infection or wound: Anytime you get a cut, scrape, or more serious wound, your body rushes fluid and white blood cells to the area. That causes swelling. If it lasts longer than 2-3 weeks, see a doctor.

If the wound gets infected, you could have more swelling. Swelling is normal for a few days. It should peak around day 2 and start to improve. If you have diabetes or another condition that affects your immune system, see your doctor. Learn more about the signs of a skin infection.

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What Should I Do About My Swollen Legs?

You can try these home remedies to ease the swelling:

Cut back on salty foods.
Wear compression stockings.
Get exercise every day.
On long car rides, switch positions and stop for breaks as often as you can.
When you fly, get up from your seat and move around as much as possible.
Raise your legs above your heart level for half an hour, several times a day.
But since leg swelling can be a sign of something serious, don’t ignore it. If you notice other symptoms, especially leg pain, shortness of breath, or extreme fatigue, call your doctor right away.