Wound healing is a complex biological process that moves through several distinct phases to repair damaged tissue. When a wound is open, the body works to fill the defect. One of the most visible signs of this repair effort is the formation of granulation tissue, which serves as a temporary foundation for new skin. Understanding the appearance of this tissue helps patients monitor their healing progress.
What Granulation Tissue Is and Its Healthy Appearance
Granulation tissue is temporary connective tissue and tiny blood vessels that develop in the wound bed during the proliferative phase of healing. Its presence indicates the wound has moved past the initial inflammatory stage and is actively repairing itself. This tissue is named for its characteristic moist, bumpy, or granular texture, often described as having a cobblestone or “beefy” appearance.
The color of healthy granulation tissue is a bright, vibrant pink to a beefy red. This intense red coloration results from the dense network of newly formed capillaries supplying the area, signaling excellent blood flow and oxygenation. The more intense the red color, the better the blood supply, indicating the tissue is receiving the nutrients necessary for reconstruction. Healthy granulation tissue is usually soft and may bleed easily with gentle contact due to the fragility of these new, thin-walled blood vessels.
The Biological Process of Tissue Formation
The formation of this vibrant tissue is a cellular process that begins when the wound needs to be filled from the base upward. Fibroblasts migrate into the wound site and begin to lay down a scaffold of extracellular matrix, initially composed of a weaker type of collagen. This matrix provides the structural framework for the new tissue that will eventually replace the defect.
Simultaneously, angiogenesis occurs, which is the growth of new capillaries from existing blood vessels. These new blood vessels deliver the oxygen, nutrients, and immune cells required to sustain the rapidly growing tissue, explaining the characteristic red color. Without this vascularization, tissue formation would stall, preventing the wound from progressing toward closure. The initial weaker collagen is later replaced by stronger, more stable collagen as the tissue matures into a scar.
When Granulation Tissue Color Signals a Problem
Deviations from the bright red or pink color of healthy tissue can signal underlying problems that are impeding the healing process. If the granulation tissue appears pale pink or white, it often suggests poor blood supply (ischemia), meaning the tissue is not receiving adequate oxygen and nutrients. This hypotrophic tissue may also appear smoother than the bumpy texture of healthy tissue.
A yellow or greenish color in the wound bed can indicate slough (a collection of dead cells and debris) or a bacterial infection. Slough delays healing and must often be removed for the wound to progress. If the tissue appears dark red, dusky, or spongy, it may be hypergranulation—an overgrowth that rises above the skin’s surface, often associated with infection or excessive moisture. Dark brown or black signifies necrotic tissue (eschar), which is dead tissue that must be addressed by a healthcare professional to prevent further complications. Any persistent change in color, increased pain, or foul odor should prompt a consultation.