January 21, 2025 | Net Health
10 min read
Granulation Tissue: Wound Healing’s Secret Weapon
Let’s start by saying that granulation tissue is less like a type of wound and more like a type of tissue you might see in a wound. It isn’t quite like an abrasion wound, puncture, or the others you might see come your way regularly. However, it plays a role in all wounds and the different ways the healing processes progress.
Healthy red granulation tissue is often found in shallow wounds with irregular borders, particularly in cases of chronic lipodermatosclerosis and venous stasis ulceration. On top of being something you might not see every day, it has a unique appearance that can leave patients and some providers uncertain about the wound site before them. Is it supposed to stick out of a wound and have a dark red color, or should it stay nestled within the wound and have a light red appearance?
If you have questions like these and want a refresher on granulation tissue, we’ve got you covered. Keep reading to gain insight into how granulation impacts your role as a wound care provider.
What Is Granulation Tissue in a Wound?
Granulation tissue is new, highly vascular connective tissue that grows from a wound’s base. When granulation tissue forms fills in the wound bed. It’s kind of like a scaffold, or supporting foundation, for the creation of new blood vessels and tissue. Granulation tissue forms during the proliferative phase of wound healing, playing a critical role by developing new blood vessels and filling the wound bed, which distinguishes it from scar tissue.
This contractile organ plays an essential part in the wound-healing process, which includes four stages
- Hemostasis: Immediately following injury, when clotting occurs to close the wound
- Inflammatory: Helps to control bleeding and prevent infection by releasing white blood cells, enzymes, and more
- Proliferative: Rebuilding the wound using new tissue
- Remodeling/Mature: Collagen remodels, injured skin becomes stronger and more flexible, and the wound fully closes
The Granulation Tissue Wound Healing Framework
In addition to those stages mentioned above, there are also different types of wound healing.
The granulation tissue framework fills wounds that heal by secondary intention, meaning that the wound is intentionally left open so it can close naturally. In short, it relies on the body’s own healing mechanisms.
With secondary wound healing, the wound edges cannot be approximated and thus cannot be closed together neatly and easily using sutures because they’re too far apart. This may be due to there not being enough skin to draw the edges together without slowing or stopping the normal flow of blood or other bodily fluids. Providers may also choose this method if it appears that the wound area is colonized with bacteria or unclean.
Compared to wounds that close by primary intention (e.g., surgery), those healing by secondary intention have a greater inflammatory reaction in and surrounding the wound. They also encompass more abundant granulation tissue inside the tissue injury.
In chronic wounds, the healing process is often prolonged due to factors like infection and poor vascularization, leading to the formation of unhealthy granulation tissue.
What Does Granulation Tissue in a Wound Look Like?
The sight of a wound with a lot of granulation tissue may make some people believe there’s a big problem, given that discoloration and texture are often signs of infection as well. This is especially the case when considering how its appearance changes as it advances through the different healing stages.
For instance, a healthy granulation tissue wound initially has a moist yet bumpy uneven texture and pink to bright red appearance. Its rough, cobblestone-like semblance results from the newly-created tissue and blood vessels, but it’s soft and painless to the touch. As healing progresses, granulation tissue begins to look smoother, glossier, and more organized.
While it might look alarming, it’s important to clarify that granulation tissue isn’t bad. You shouldn’t remove it as long as it’s healthy because it encourages wound closure. In fact, granulation tissue is seen as a hallmark of healing, so it’s important to be very gentle. That doesn’t mean that other wounds don’t require debridement, however, and it’s definitely important to be able to tell the difference.
Excess granulation tissue, however, can disrupt the healing process and lead to complications such as delayed wound closure and increased infection risk, necessitating intervention from healthcare professionals.
Poor wound care and other factors can lead to unhealthy granulation, which we’ll get into later. Bonus Tip: Oral wounds may form granulation tissue that’s white or cream in color. It may indicate that the patient has a dry socket or infection if it’s associated with pain.
What Is Granulation Tissue Made of?
According to the Ohio State College of Medicine, granulation tissue is comprised mainly of proliferating capillaries and cells, including microscopic blood vessels. These microscopic blood vessels play a crucial role in granulation tissue by protecting the wound surface from infections, facilitating tissue filling and growth, and serving as a temporary replacement for damaged tissue until it is replaced by scar tissue. Most of the cells are fibroblasts and inflammatory cells, like neutrophils, macrophages, plasma cells, and lymphocytes. Myofibroblasts play a key role, as well.
Let’s explore the function of some of those cells now.
Fibroblasts
Considered the most common cell type in connective tissue, fibroblasts appear early on in the granulation tissue wound healing process. They create the granulation tissue extracellular matrix or ECM. The ECM consists of type III collagen at first, a feebler type of collagen primarily used as a structural component for blood vessels. As the tissue develops, it’s replaced with type I collagen, a much stronger collagen form used for wound healing and scar formation.
Neutrophils and Macrophages
Immune cells like these primarily aid in protecting the wound from cellular debris and invading pathogens. They respond to inflammation, a central component of the inflammatory stage, as the name suggests, and aim to maintain homeostasis so the wound can heal properly.
Myofibroblasts
Following the formation of granulation tissue, fibroblasts evolve into myofibroblasts. Myofibroblasts are the wound construction workers, using their contractile properties to promote wound contraction and closure using granulation tissue. As the primary source of ECM proteins, they remodel this matrix to encourage fibrosis and scarring.
Research suggests that excess myofibroblasts can lead to tissue contractures, while too little can impair wound healing.
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What Role Does Granulation Tissue Play in Wound Healing?
Earlier, we mentioned how granulation tissue plays a prominent role in the wound healing process, but can you guess in which stage this occurs? If you said the proliferative stage, you’re correct!
When you see granulation tissue, the wound is likely moving from the inflammatory stage to the proliferative one. It usually appears approximately three to six days after an injury.
Several actions occur during the proliferative stage. However, granulation tissue specifically serves three primary functions: immune, proliferative, and temporary plug.
- Immune: Granulation tissue works to protect the wound by acting as a barrier to external contaminants. It uses the cells we mentioned above to handle this task.
- Proliferative: As a proliferator, it fills the wound with new tissue and vasculature to eliminate dead space. Over time, it also aids in decreasing the size of the wound.
- Temporary Plug: Granular wounds act as a transitional replacement for normal dermis. It replaces necrotic tissue until it advances into scar tissue during the remodeling stage.
Depending on the severity of the injury, these processes can last several days to many weeks.
The Different Forms of Granulation Tissue Wounds
If a granulation tissue wound is healthy, it’s typically only refered to as such. However, if it’s unhealthy, it’ll likely fall into either one of two categories: hypotrophic granulation tissue and hypertrophic granulation tissue.
We’ll explore both below.
Hypotrophic Granulation Tissue in a Wound
First, let’s break down the word hypotrophic, which means something exhibits hypotrophy, degeneration that has occurred in an organ or tissue due to cell loss. Therefore, a hypotrophic granulation tissue wound lacks cells likely needed for proper wound healing.
Hypotrophic granulation tissue has a somewhat pale pink appearance, lacks vascularity, and begins bleeding at the slightest touch. A healthy granulation tissue wound doesn’t bleed easily. Therefore, if this occurs, it may signal that the wound isn’t getting the oxygen and nutrients it needs to heal due to poor blood flow.
A Hypertrophic Granulation Tissue Wound (aka Hypergranulation Tissue)
If hypo means that something is “below” or “less than normal,” then hyper tells you that something is “over” or “in excess.” As a result, hypertrophic granulating wound occurs when there’s an overgrowth of this tissue, rather than the lack thereof seen in hypotrophic granulation tissue.
Since a granulating wound is deemed the hallmark of healing, isn’t having more of it a good thing? Well, not quite. Sometimes, too much of a good thing is actually bad (see also: cheesecake).
Proud flesh, or exuberant tissue, as it’s occasionally called, protrudes from the wound and grows outside the wound margins. It may have a dark-dusky red appearance. This excess granulation, known as hypergranulation tissue, tells wound care experts that something is standing in the way of proper wound healing. Hypergranulation tissue can hinder the healing process and may need to be removed to promote better recovery. Some causes include poor perfusion, excess moisture, infection, and/or ischemia. Timely intervention is essential. Without it, the wound may not close, leading to a chronic wound. Once it becomes a chronic wound.), it may be covered by shiny yellow or white fibrinous tissue.
How Do You Treat a Granulation Tissue Wound?
The way you treat a granulation tissue wound ultimately depends on whether it’s healthy or not. If it’s healthy, just ensure it’s protected by using some form of dressing. Change the dressings out every other day (or more often if needed) to ensure the granulation tissue is in a moist, warm, and clean environment.
If the granulation tissue wound is unhealthy, you’ll want to consider the suggestions below.
Treating a Hypotrophic Granulation Wound
If the granulating wound isn’t getting the nutrients it needs, try to identify the underlying cause. Proper healing can’t take place until that’s addressed.
Sometimes, hypo-granulation occurs from ongoing inflammation, trauma, chronic conditions that inhibit wound healing, or even pressure on the wound site. Trauma could result from improper care, such as using dry dressings, excessive packing, and high-pressure irrigation. Once you determine the cause, you can manage the situation.
For example, type 2 diabetes is known to impair perfusion and the cellularity of granulation tissue. Therefore, treatment may involve managing glucose levels by having the patient take certain medications, following a nutritious diet, and/or making lifestyle adjustments. Once that’s under control, it should stimulate granulation tissue formation.
Treating a Hypertrophic Granulation Wound
Treating proud granulation also requires wound care experts to learn the underlying cause. However, there are other steps you can take to manage the situation.
If there’s no infection or the infection has been cleared, consider the following options
- Conduct simple cautery with silver nitrate
- Apply topical steroids as needed to reduce inflammation
- Complete debridement if there’s overlying fibrous tissue
Keep in mind that treatment ultimately depends on how the wound occurred and where it’s located on the body. For instance, hyper-granulation is commonly observed during the postnatal period, and treatment may involve just using topical silver nitrate or performing surgery.
How Does a Granulation Wound Differ from Other Wounds?
Granulation tissue differs because they’re not wounds at all. In fact, it’s the body’s response to an injury.
So, if someone experiences a minor puncture wound and it is healing correctly, typically secondary intention, it’ll start to fill in with granulation tissue. The same applies if a provider decides that healing a wound by primary or tertiary intention is better. In both scenarios, it’s still expected that granulation tissue will form.
In short, all wounds should experience granulation tissue formation during the proliferative stage, as that’s what’s needed to help the wound close and strengthen. They only become problematic when the granulating wound is deficient or being formed in excess. However, granulation tissue will function as intended once those issues are corrected.
The Hallmark of Healing: Healthy Granulation Tissue
It’s clear that granulation tissue is a pretty important part of wound healing, as it tells providers the direction a patient’s wound is going in.
However, let’s face it: sometimes, it’s hard to tell if the granulation you see is healthy or not. Even further, what if it looks like granulation tissue, but it’s not? Such scenarios can cause wound care clinicians, from nurses to physicians, to misdiagnose a wound, leading to further complications.
Fortunately, this is where technology can help. AI-powered wound imaging platforms designed to improve wound assessment accuracy and decrease the time it takes to complete wound evaluations can be immensely helpful in properly diagnosing and determining the right treatment plan. This powerful tool will help you spend more time with patients, promoting better health outcomes and boosting overall patient satisfaction.
With all these tools in your arsenal, you’re more than ready to deal with the next case of unhealthy granulation tissue coming your way.