👉 Extravasation is a medical condition in which the body's response to injury or infection leads to fluid buildup around the blood vessels, causing swelling and pain. It can occur when the body's immune system attacks healthy tissues, such as skin, organs, or bones, leading to an accumulation of fluid. This excess fluid can cause various symptoms like swelling, pain, bruising, and difficulty breathing. Extravasation is a common side effect of certain medications and procedures, but it