Why Do Our Bodies Swell? 12 Surprising Reasons

Swelling, also known as edema, is the name for an increase in size or change in shape of an area of the body.

Swelling is a symptom of a variety of conditions, but there is always an underlying cause. Sometimes, the source of swelling can be serious and require immediate medical attention.

So, if you notice a swollen area on your body, it’s important to identify the reason.

Types of Swelling

Body parts swell when the body retains fluid or collects it in a certain tissue, joint, or other area. Swelling can be internal or external, localized or generalized.

• External swelling, typically affecting skin or muscles, is visible and usually due to an insect bite, illness, or injury and commonly will heal on its own within two weeks.
• Internal swelling, which affects organs or other areas inside the body, usually has a more serious cause and can have more intense pain.
• Localized swellingrefers to swelling in just one area of the body, such as from a bee sting or an ankle sprain.
• Generalized swelling affects the whole body and often is the result of a major traumatic injury or allergic reaction.

Reasons for Swelling

There can be many causes of swelling:

• Injury– Swelling often occurs at the site of injuries – including strikes to the body, sprains, muscle strains, and bone fractures – because small tears in the surrounding blood vessels cause fluid to leak into the area.
• Infection– Pockets of pus or other fluids may form at the site of an infection. These fluids may actually help to resolve the infection, as their presence indicates that infection-fighting white blood cells are on the job.
• Allergic reaction– Large areas of the body may swell during an allergic reaction, which requires medical attention, especially if swelling of the face, tongue, or throat occurs.
• Burns/chemical burns – Burns cause tender, inflamed skin with or without a blister, depending on the depth of the burn.
• Insect bites– Most insect stings and bites result in redness and swelling. If extreme swelling, redness, and itching occur, you may be having an allergic reaction to the bite.
• Inflammation– Joints or tendons may swell after repeated motion or overuse.
• Autoimmune/chronic diseases– Chronic illnesses may cause circulation problems that result in the buildup of fluid throughout the body.
• Pregnancy– Pregnant women often experience swelling of the hands and feet, especially as pregnancy progresses.
• Menstruation– Many women retain fluid during menstruation, resulting in swelling or bloating.
• Standing, sitting, or walking for a long time in the heat – All may cause swelling of the lower legs and feet.
• Medications -- Some common medications may cause swelling, including NSAIDs (ibuprofen, naproxen sodium) and steroids.
• Surgery– Some swelling is normal after surgery at the site of an incision or affected area.
• Other serious medical conditions -- including cirrhosis, liver/kidney disease, and heart disease.

How to Treat Swelling

Often, swelling will go down on its own over time. You can take steps to help reduce swelling.

• Get plenty of rest to protect the affected area.
• Elevate the swollen area to above your heart.
• Move the swollen area to help get blood flow back to the heart, especially if the swelling is in the legs.
• Use pressure either from compression stockings or sleeves or simply apply pressure with your hands in a massage-like fashion.
• Reduce the amount of salt you are consuming as it may play a role in increased swelling.
• For more serious swelling, the underlying cause may need to be treated by doctors. An exam and/or imaging tests can help determine issues.
• Your doctor may be able to prescribe medication or recommend other methods to reduce the swelling.

Your doctor will likely ask you questions such as:

• Have you experience edema before?
• Have you experienced shortness of breath as well?
• Do you drink alcohol?
• Are your symptoms constant or on and off?
• Does the severity of your swelling decrease after a night’s rest?
• What does your diet consist of?
• Are you urinating the same as usual?

If you notice sudden, extreme, or unexplained swelling, or if your swelling is due to a serious injury or medical condition, call your doctor or seek medical attention immediately or visit a UPMC Urgent Care location.