Swelling: Causes and When to Worry

Local swelling vs generalized swelling

Causes of local swelling

Injury

Sprains, strains, fractures and bruises cause swelling within minutes to hours as blood and fluid leak into the tissues. Swelling that appears very quickly within 1 to 2 hours often means bleeding inside a joint.

Inflammation of tendons and joints

• Tendinitis and tenosynovitis: swelling along a tendon. De Quervain's tenosynovitis causes swelling and pain on the thumb side of the wrist, worse with gripping and lifting a baby.
• Arthritis and gout: swelling, warmth and stiffness in a joint.
• Bursitis: soft, fluid-filled swelling over the elbow, knee or shoulder.

Infection

Cellulitis and abscesses cause red, hot, painful, spreading swelling, sometimes with fever.

Allergic swelling

Insect bites and stings cause local swelling that can be large but settles within days. Angioedema is deeper swelling of the lips, eyelids, tongue, hands or genitals. Recurrent swelling of the skin without hives may be hereditary angioedema or a reaction to ACE inhibitor blood pressure medicines.

Blood clots

A deep vein thrombosis causes swelling, aching and warmth in one leg, or less often an arm. A swollen, bluish arm can mean a clot in the arm or chest veins, which can follow an IV line, pacemaker or repetitive overhead arm use.

Cysts and lumps

A ganglion cyst causes a smooth, round swelling on the back or front of the wrist. Lipomas and other lumps cause painless swellings elsewhere.

Lymphedema

Lymphedema is swelling from a blocked or damaged lymph system, often in an arm after breast cancer surgery or radiotherapy, or a leg after pelvic surgery. It feels heavy and tight and develops gradually.

Swelling in common locations

Swelling above the wrist

Sudden swelling on the back or thumb side of the wrist is commonly from a ganglion cyst, de Quervain's tenosynovitis, a wrist sprain or fracture after a fall on an outstretched hand, gout or pseudogout, or an infection. Swelling with redness and fever needs same-day care. Swelling and stiffness in the wrist and hand together, especially in both hands with morning stiffness, can be rheumatoid arthritis. See wrist swelling.

Swelling on the top of the shoulder

A bump on top of the shoulder after a fall may be an AC joint separation. Other causes include bursitis, fluid in the shoulder joint from a rotator cuff tear or arthritis, a lipoma, or infection. See shoulder swelling.

Swelling of the scrotum

Swelling with severe itching of the scrotum usually comes from skin conditions such as contact dermatitis, fungal infection (jock itch) or scabies. Painful swelling may be epididymitis, a hernia or torsion.

Throat swelling

A sense of throat swelling can come from tonsillitis, allergic reactions, angioedema or thyroid enlargement. Swelling with breathing trouble is an emergency.

Causes of generalized swelling (edema)

• Heart failure: a weak heart lets fluid back up into the legs and lungs. Swelling of both ankles with breathlessness and tiredness. See heart failure.
• Kidney disease: the kidneys cannot remove salt and water. Nephrotic syndrome causes swelling around the eyes in the morning and foamy urine.
• Liver disease: low albumin and high pressure cause swelling of the belly (ascites) and legs.
• Chronic venous insufficiency: leaky leg veins cause swelling that is worse at the end of the day, with skin darkening and varicose veins. See peripheral edema.
• Medicines: calcium channel blockers (amlodipine), NSAIDs, steroids, some diabetes drugs and hormones.
• Pregnancy: mild ankle swelling is normal; sudden swelling of the face and hands may signal preeclampsia.
• Heat, long sitting and long flights.
• Underactive thyroid and severe malnutrition.

How doctors find the cause

A doctor will ask when the swelling started, whether it is on one or both sides, about injury, pain, breathing problems, medicines and other illnesses. They will press on swollen areas to check for pitting, and examine the heart, lungs, belly and joints.

Tests may include blood tests (kidney and liver function, albumin, thyroid, BNP for heart failure, D-dimer for clots), urine tests for protein, ultrasound of veins, joints or lumps, X-rays after injury, and an echocardiogram.

How to reduce swelling

For injuries (first 48 to 72 hours)

• Rest the area.
• Ice wrapped in a cloth for 15 to 20 minutes every 2 to 3 hours.
• Compression with an elastic bandage that is snug but not tight.
• Elevation above heart level as much as possible.

For fluid retention in the legs

• Raise your legs when sitting and lying down.
• Walk regularly; calf muscle contractions pump fluid back up.
• Wear compression stockings if your doctor confirms your circulation is adequate.
• Reduce salt intake.
• Avoid sitting or standing still for long periods.

Do not take diuretics ("water pills") without a diagnosis. Treating the underlying cause, such as heart failure, kidney disease or a medicine side effect, is what brings lasting improvement.

Frequently asked questions

What causes sudden swelling above the wrist?

Sudden swelling above the wrist is commonly caused by a sprain or fracture, a ganglion cyst, de Quervain's tenosynovitis, gout or pseudogout, an insect bite or infection. Red, hot swelling with fever needs same-day care. Swelling after a fall should be X-rayed to rule out a fracture.

What is peripheral swelling?

Peripheral swelling, or peripheral edema, is fluid buildup in the lower legs, ankles and feet, and sometimes the hands. Common causes include vein problems, heart failure, kidney or liver disease, pregnancy and medicines such as amlodipine. Swelling of one leg only may be a blood clot.

What causes recurrent swelling of the skin?

Recurrent episodes of deep skin swelling, often of the lips, eyes, hands or feet, are called angioedema. Causes include allergies, ACE inhibitor medicines and hereditary angioedema, an inherited condition. Swelling with hives is usually allergic. See a doctor, and seek emergency care if the throat or tongue swells.

When is swelling an emergency?

Swelling is an emergency when it affects the lips, tongue or throat, comes with trouble breathing, affects one leg with chest pain or breathlessness, or follows an injury with severe pain, numbness or a pale or cold limb. Call 911 for these.

What is the fastest way to reduce swelling?

For injuries, rest, ice, compression and elevation work best in the first 2 to 3 days. For leg swelling from fluid, raising the legs above heart level, walking and compression stockings help. Lasting improvement depends on treating the cause.