Overview
Swelling is an increase in size or fullness of a body part. It may happen because fluid collects in the tissues, a joint becomes inflamed, or the body reacts to injury, infection, or allergy. Swelling may be obvious on the outside or felt deeper inside the body.
Key Symptoms
The swollen area may look puffy, stretched, shiny, or larger than usual. It may also feel tight, painful, warm, stiff, heavy, or tender. Some people notice trouble moving a joint, shoes or rings feeling tighter, or a dent left after pressing on the skin.
Causes and Risk Factors
Common causes include sprains, blows, insect bites, infections, allergic reactions, and joint inflammation. Swelling can also happen when the body retains fluid, such as with long periods of sitting or standing, pregnancy, some medicines, or health conditions affecting the heart, kidneys, liver, veins, or lymphatic system. Risk factors depend on the cause and can include recent injury, surgery, reduced movement, heat, high salt intake, and certain chronic illnesses.
Who Is Affected
Swelling can affect people of any age. It is common after minor injuries and can also occur during pregnancy or with long travel and prolonged standing. Older adults and people with long-term medical conditions may be more likely to have repeated or persistent swelling.
Prevention
Some swelling can be reduced by protecting against injuries, moving regularly during long travel or desk work, and managing long-term health conditions with medical guidance. Elevating the affected limb and avoiding long periods in one position may help with mild fluid buildup. Preventing allergic triggers and caring for cuts or bites promptly may also lower the chance of swelling from allergy or infection.
Diagnosis and Tests
A healthcare professional will usually ask where the swelling is, when it started, whether it is painful, and what other symptoms are present. They may examine the area and look for signs such as redness, warmth, tenderness, skin changes, or swelling in both sides of the body. Depending on the situation, tests may include blood tests, urine tests, imaging such as ultrasound or X-ray, or other studies to look for the cause.
Treatment Categories
Treatment depends on the cause of the swelling. It may involve rest and support after an injury, treatment for infection or inflammation, changes to medicines, or care for conditions affecting circulation or body organs. Do not ignore unexplained swelling, especially if it is new, severe, or getting worse.
When to Seek Medical Care
Seek medical care if swelling lasts more than a few days, keeps returning, is getting worse, or affects daily activities. You should also get checked if swelling happens with pain, redness, warmth, fever, skin sores, sudden weight gain, or swelling in the face, abdomen, or only one leg. Swelling during pregnancy, or swelling after surgery, should also be discussed with a healthcare professional.
When It May Be an Emergency
Get emergency help right away if swelling happens with trouble breathing, wheezing, chest pain, fainting, or swelling of the lips, tongue, or throat. Emergency care is also important for sudden swelling in one leg with pain or shortness of breath, or for swelling after a serious injury. Rapidly worsening swelling, especially with severe pain or signs of infection, should be treated urgently.