Have you ever had a sprain or a bee sting that swells up like a balloon? The swelling is called edema, a normal response to injury and inflammation. In the case of a sprain, it helps to rest, apply ice, use compression and elevate the injury. For a bee sting, remove the stinger, wash with soap and water and apply cold compresses or ice (unless you are allergic to bee stings, in which case, use your EpiPen and seek medical treatment). What about edema that appears without known injury?