A collagen dressing is a type of wound dressing that is made with a form of collagen to aid in the body's healing processes. Collagen is a category of structural proteins that are naturally present in almost every part of the human body and are especially common in connective tissue. In a wound, the application of these proteins protects the body's own collagen from degradation because of over-activity of enzymes so that body has the building materials needed to repair the damage.
In normal wound healing, special enzymes called matrix metalloproteinases (MMPs) break down damaged or malformed collagen so that it can't be used mistakenly in building the scaffolding for the new tissue to grow on. Wounds often become chronic when too many MMPs are present, because they break down the healthy collagen as well, but when a wound dressing containing collagen is used, the MMPs are kept busy breaking down that collagen, and the body's own healthy collagen is protected. A collagen dressing provides other benefits as well, such as absorbing fluids that are draining, maintaining a wet wound bed and providing a barrier for external sources of infection. In addition, these dressings do not stick to the newly forming tissue, so they do not leave behind any fibers or damage the tissue when the dressings are changed. There also is some evidence to show that these dressings speed up production of fibroblasts, cells that make collagen and other parts of extracellular structure, and that they attract fibroblasts from other areas to the wound site.
There are many variations on the construction of the collagen dressing, and it collagen from one of several sources might be used. Collagen that has been harvested from horses, cows, birds or pigs is purified for medical use, such as wound dressings. These dressings are available in rectangular blocks, membranes with a non-stick backing, sheets, ropes and pastes. Even the solid forms of collagen generally become a gel as they absorb fluid from the wound and conform to the surface so that they have contact with the entire wound. Some of the products are 100 percent collagen, but many of them are blended with a substance such as oxidized regenerated cellulose that is bonded to an antimicrobial agent.
Types of wounds that call for the application of a collagen dressing include chronic or stalled wounds and wounds with large surface areas. Pressure ulcers, or bed sores, and similar ulcers caused by complications of diabetes often become chronic and benefit from a collagen dressing. Wound dressings that include collagen are very helpful for burns that don't affect the entire thickness of the skin and sites where the skin has been removed for transplant to another site or another person. Surgical wounds that have ruptured and infected wounds can be aided by collagen dressings as long as the infection is being controlled.