Exudate is fluid which leaks out of damaged tissues. It can be the result of trauma, inflammation, or an underlying disease process which compromises the tissue. A classic example of exudate is pus, found in some types of wounds as they heal. Depending on the quantity and quality of the fluid, exudate can help or hinder healing, and sometimes characteristics of expressed fluids reveal information about the progress of the healing. Microscopic examination can reveal more about what is inside the fluid, which can help a doctor make decisions about treatment recommendations.
Water is one of the major constituents of exudate, which should come as no surprise, since it makes up a large part of the body. The fluid also contains proteins from blood and tissue cells, and can include bacteria, lymph, and other materials as well. Some exudate weeps slowly out of damaged tissues, accumulating gradually over time, while in other cases, the fluid may seep very rapidly, building up in and around a wound.
While it may be unsightly, fluid which weeps from damaged cells can be a good thing. It often carries infectious and dead material out of the body so that they cannot continue to contribute to inflammatory processes, providing a method of flushing the body. It can also keep a wound moist, which can contribute to healing with some types of wounds, and create a filmy barrier which protects a wound from the outside. If wounds become too dry, sometimes the healing process is disrupted, and the area can be at risk of infection from microbes which take advantage of cracks in dried skin.
People often notice small amounts of exudate on bandages when they change them. The slow seepage indicates that healing is taking place under the bandage, but that inflammation is still occurring. If the exudate has a strong odor, is copious, or acquires a strange color, it may be a sign that infection has set in and more medical attention is needed to address the wound.
Exudate can also happen inside the body. Pleural effusion, in which the space around the lungs becomes filled with fluid, can be caused by exudate. Likewise, leaking fluids can lead to edema. In these cases, the body cannot express the leaking fluid as quickly as it is generated, and it creates medical complications. Treatment for buildups of fluid vary, depending on where in the body they are, the cause of the buildup, and the patient's general health.