Swelling occurs whenever the organs, skin, or other parts of your body enlarge. It’s typically the result of inflammation or a buildup of fluid. Swelling can occur internally, or it can affect your outer skin and muscles.
A range of conditions can cause swelling. Insect bites, illnesses, or injuries often result in external swelling. Internal swelling is often a side effect of a medication or the result of a serious injury.
You should seek immediate medical attention if you experience rapid, unexplainable swelling, especially if you also experience unexplained weight gain and pain.