Swelling is an increase in the size or a change in the shape of an area of the body. Swelling can be caused by:
- A collection of body fluid.
- Growth of tissue.
- Abnormal movement or position of tissue.
Most people will have swelling at some time. When it's hot and you've stood or sat in the same position for a long time, you might notice swelling in your feet and ankles. Staying in one position for any length of time increases the risk that the lower legs, feet, or hands will swell. That's because gravity normally causes body fluid to move down a limb. Swelling can also be caused by heat-related problems. One example is heat edema from working or being active in a hot environment.
Body fluid can collect in different tissue spaces of the body (localized swelling). Or it can affect the whole body (generalized swelling). Causes of localized swelling include:
- Injury to a specific body area. Bruising (hematoma) from an injury is caused by tears in the small blood vessels under the skin. Bleeding can also affect the joint (hemarthrosis) or the area that cushions and lubricates the joint (traumatic bursitis). Swelling can affect just one area. Or it may involve large sections of the body, such as swelling that occurs after a car crash.
- Infection. It can occur in a joint or under the skin. An abscess is a pocket of pus that forms at the site of infected tissue. Cellulitis is a skin infection that can cause mild or severe swelling.
- Burns. They can cause swelling at the site of the burn or in a larger area around the burn.
Inflammation that occurs when tissue is irritated by overuse or repeated motion.
- Swelling of the tendon and swelling caused by a series of small tears around a tendon (tendinosis) can occur together or on their own.
- Swelling of the sac that cushions and lubricates the joint (bursitis) can be caused by prolonged or repeated pressure. It can also be caused by activities that require repeated twisting or rapid joint movements.
- Insect bites or stings. Most insect bites or stings cause a small amount of redness or swelling. Some people have an allergic reaction to a bite or sting. They have a lot of swelling, redness, and itching.
- Other causes, such as swelling related to a sac-shaped structure with clear fluid, blood, or pus (cyst). Or swelling may be from a swollen gland, such as a salivary gland.
Causes of generalized swelling include:
- An allergic reaction. Sudden swelling of the hands and face may be a severe allergic reaction (anaphylaxis). It needs medical care right away.
- Autoimmune diseases, such as lupus, rheumatoid arthritis, and scleroderma. These diseases can cause swelling when the body produces antibodies and other cells that attack and destroy tissues in the body.
- Medicines. Some medicines change how body fluids circulate, causing swelling. Swelling may also occur as an allergic reaction to a medicine.
- Circulation problems related to certain medical conditions, such as peripheral arterial disease, heart failure, diabetes, or kidney disease. Thrombophlebitis causes swelling of an extremity when a blood clot interrupts blood flow in a vein in the arm or leg.
- Fluid that accumulates in the belly (ascites) because of other problems, such as malnutrition, cirrhosis, or liver disease.
Some people may have swelling as a reaction to a medical treatment, procedure, or surgery. Swelling from a medical treatment may be related to the procedure. Or it may be from a substance, such as dye, used during the procedure. Swelling may occur at an intravenous (IV) site used during a procedure or at an IV site used for medicines given at home. Some swelling at the site of surgery is normal, such as swelling of the arm after a mastectomy. Lymphedema is swelling that occurs in an area around lymph nodes that have been removed (such as after surgery) or injured (such as after radiation treatments).
Swelling can also be caused by the rise and fall of hormone levels within the body. Some women may notice swelling from retaining fluid during their menstrual cycles. This may be called cyclical edema, because it's related to the menstrual cycle. Some women have mild swelling in their hands or feet during pregnancy. Swelling in the feet may be more obvious in the third trimester of the pregnancy. Generalized swelling can be a sign of a pregnancy-related problem called preeclampsia.
Swelling can occur when tissues move out of their normal position, such as hernias in the abdomen.
Most of the time, swelling is mild and goes away on its own. You may not even know what caused it. Home treatment is usually all that is needed to relieve mild symptoms.
Health Tools help you make wise health decisions or take action to improve your health.
Check Your Symptoms
The medical assessment of symptoms is based on the body parts you have.
- If you are transgender or nonbinary, choose the sex that matches the body parts (such as ovaries, testes, prostate, breasts, penis, or vagina) you now have in the area where you are having symptoms.
- If your symptoms aren’t related to those organs, you can choose the gender you identify with.
- If you have some organs of both sexes, you may need to go through this triage tool twice (once as "male" and once as "female"). This will make sure that the tool asks the right questions for you.
Many things can affect how your body responds to a symptom and what kind of care you may need. These include:
- Your age. Babies and older adults tend to get sicker quicker.
- Your overall health. If you have a condition such as diabetes, HIV, cancer, or heart disease, you may need to pay closer attention to certain symptoms and seek care sooner.
- Medicines you take. Certain medicines, such as blood thinners (anticoagulants), medicines that suppress the immune system like steroids or chemotherapy, herbal remedies, or supplements can cause symptoms or make them worse.
- Recent health events, such as surgery or injury. These kinds of events can cause symptoms afterwards or make them more serious.
- Your health habits and lifestyle, such as eating and exercise habits, smoking, alcohol or drug use, sexual history, and travel.
Try Home Treatment
You have answered all the questions. Based on your answers, you may be able to take care of this problem at home.
- Try home treatment to relieve the symptoms.
- Call your doctor if symptoms get worse or you have any concerns (for example, if symptoms are not getting better as you would expect). You may need care sooner.
Pain in adults and older children
- Severe pain (8 to 10): The pain is so bad that you can't stand it for more than a few hours, can't sleep, and can't do anything else except focus on the pain.
- Moderate pain (5 to 7): The pain is bad enough to disrupt your normal activities and your sleep, but you can tolerate it for hours or days. Moderate can also mean pain that comes and goes even if it's severe when it's there.
- Mild pain (1 to 4): You notice the pain, but it is not bad enough to disrupt your sleep or activities.
Swelling can be a sign that you are having an allergic reaction to a medicine. This can happen with almost any medicine.
Many prescription and nonprescription medicines also may cause swelling as a side effect. A few examples are:
- Hormones, such as birth control pills and hormone therapy used to treat menopause symptoms.
- Some blood pressure medicines.
Symptoms of difficulty breathing can range from mild to severe. For example:
- You may feel a little out of breath but still be able to talk (mild difficulty breathing), or you may be so out of breath that you cannot talk at all (severe difficulty breathing).
- It may be getting hard to breathe with activity (mild difficulty breathing), or you may have to work very hard to breathe even when you’re at rest (severe difficulty breathing).
Severe trouble breathing means:
- You cannot talk at all.
- You have to work very hard to breathe.
- You feel like you can't get enough air.
- You do not feel alert or cannot think clearly.
Moderate trouble breathing means:
- It's hard to talk in full sentences.
- It's hard to breathe with activity.
Mild trouble breathing means:
- You feel a little out of breath but can still talk.
- It's becoming hard to breathe with activity.
Symptoms of a severe allergic reaction (anaphylaxis) may include:
- The sudden appearance of raised, red areas (hives) all over the body.
- Rapid swelling of the throat, mouth, or tongue.
- Trouble breathing.
- Passing out (losing consciousness). Or you may feel very lightheaded or suddenly feel weak, confused, or restless.
A severe reaction can be life-threatening. If you have had a bad allergic reaction to a substance before and are exposed to it again, treat any symptoms as an emergency. Even if the symptoms are mild at first, they may quickly become very severe.
Seek Care Today
Based on your answers, you may need care soon. The problem probably will not get better without medical care.
- Call your doctor today to discuss the symptoms and arrange for care.
- If you cannot reach your doctor or you don't have one, seek care today.
- If it is evening, watch the symptoms and seek care in the morning.
- If the symptoms get worse, seek care sooner.
Make an Appointment
Based on your answers, the problem may not improve without medical care.
- Make an appointment to see your doctor in the next 1 to 2 weeks.
- If appropriate, try home treatment while you are waiting for the appointment.
- If symptoms get worse or you have any concerns, call your doctor. You may need care sooner.
Seek Care Now
Based on your answers, you may need care right away. The problem is likely to get worse without medical care.
- Call your doctor now to discuss the symptoms and arrange for care.
- If you cannot reach your doctor or you don't have one, seek care in the next hour.
- You do not need to call an ambulance unless:
- You cannot travel safely either by driving yourself or by having someone else drive you.
- You are in an area where heavy traffic or other problems may slow you down.
Call 911 Now
Based on your answers, you need emergency care.
Call 911 or other emergency services now.
Sometimes people don't want to call 911. They may think that their symptoms aren't serious or that they can just get someone else to drive them. Or they might be concerned about the cost. But based on your answers, the safest and quickest way for you to get the care you need is to call 911 for medical transport to the hospital.
Mild swelling will usually go away on its own. Home treatment may help relieve symptoms.
Swelling and pain are very common with injuries. When you have swelling, make sure to look for other symptoms of injury that may need to be checked by your doctor.
If you have a medical condition that may cause swelling, follow your doctor's instructions on how to treat your swelling.
- Get some rest.
Protect a sore area. Stop, change, or take a break from any activity that may be causing your pain or soreness.
- Elevate the area if you can.
Prop up the injured or sore area on pillows while you apply ice and anytime you sit or lie down. Try to keep the area at or above the level of your heart to help reduce swelling.
- Keep moving.
Don't sit or stand for long stretches of time. Exercising the legs decreases the effect of gravity, so swelling goes down.
- Watch what you eat.
A low-sodium diet may help reduce swelling.
- Stay hydrated.
Drink plenty of fluids to help prevent swelling caused by dehydration.
- Stay cool.
Keep your skin cool in hot environments.
When to call for help during self-care
Call a doctor if any of the following occur during self-care at home:
- Swelling that increases or spreads.
- New or worse trouble breathing.
- New fever.
- Decrease in urination.
- Symptoms occur more often or are more severe.
Preparing For Your Appointment
You can help your doctor diagnose and treat your condition by being prepared for your appointment.
Current as of: March 9, 2022
Author: Healthwise Staff
William H. Blahd Jr. MD, FACEP - Emergency Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine