What is the Relationship Between Inflammation and Swelling?

Henry Gaudet

Inflammation and swelling are so closely related that some people use the terms interchangeably, but they are not synonymous. Put simply, an inflammation is the body's reaction to physical damage or some other irritant, and swelling is one symptom that might be caused by an inflammation. Other symptoms of inflammation include redness, heat and pain. Although swelling and inflammation often occur together and inflammation is a very common cause of localized swelling, swelling might have other causes as well, and general swelling affecting the entire body is not likely to be caused by inflammation.

Inflammation may occur as a result of a physical injury.
Inflammation may occur as a result of a physical injury.

Irritation or damage to the body’s cells triggers an inflammation as a defensive response. This damage might take the form of a physical injury. Burns, frostbite and chemical irritants will cause inflammation as well. Inflammation can also be caused by pathogens infecting the cells or by an immune response.

Frostbite may cause inflammation.
Frostbite may cause inflammation.

The body triggers an inflammation to repair and minimize the damage caused by these irritants. Capillaries at the site of the inflammation dilate, slowing the flow of blood out of the area and allowing white blood cells to attack foreign cells. This is what causes inflamed areas to redden and feel hot. Pain receptors are also stimulated, encouraging the victim to protect the area.

Over-the-counter anti-inflammatory medications are a common treatment for inflammation and swelling.
Over-the-counter anti-inflammatory medications are a common treatment for inflammation and swelling.

Another important response is swelling. Inflammation causes the area to fill with fluid seeping from the capillaries. Swelling not only pads and protects the site of the irritation, proteins in the fluid also help carry antibodies that help fight infection and speed healing. In the case of injury, fluid pressure helps to slow bleeding, giving the blood time to clot.

When inflammation and swelling are severe, steps can be taken to ease the symptoms. Depending on the nature of the irritation, ice can be applied to dilate the blood vessels, thus easing the pain, redness and swelling. Over-the-counter anti-inflammatory medications such as aspirin, acetaminophen and ibuprofen offer relief from inflammation as well as swelling. Inflammation and swelling indicate that there is a problem, and especially severe or prolonged inflammation should be seen by a medical professional.

Although inflammation and swelling often occur together, swelling might have other causes, varying in severity from mild discomfort to quite serious. Swelling associated with inflammation is typically focused on a specific area or injury. If swelling is not localized, then other causes should be considered. Patients experiencing extreme, chronic or otherwise worrisome swelling should consult with a doctor.

Swelling can be reduced by applying an ice pack.
Swelling can be reduced by applying an ice pack.

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Discussion Comments


I have allergies to many insect bites. If I get an insect bite, that area becomes inflamed, very red, swollen and itchy. It takes at least a week for these symptoms to go away.

How does this happen? Is the insect releasing something into my skin that causes this type of response? Or is it because I have a sensitive, allergy-prone skin?


@literally-- It's possible but usually there is some swelling involved, even if it's minor and difficult to see with the eye.

When there is an infection or injury, we have an inflammatory response like the article said. Different types of body cells rush to the area first to kill bacteria and then to remove dead cells out. This causes swelling.

But swelling is most when there is acute inflammation and less with minor or chronic inflammation. For example, arthritis is an inflammatory condition, but it doesn't cause as much swelling as an infected wound or a broken arm.


Does this mean that we can have inflammation in the body without swelling?

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