Epithelial Versus Granulation: Is It Full- or Partial-Thickness and What’s the Significance?

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Holly M. Hovan MSN, APRN, GERO-BC, CWOCN-AP

Introduction

In chronic wound management, clinicians often see and treat both partial- and full-thickness wounds. These wounds may present as pressure injuries or other wound types, including, although not limited to:

  • Burns
  • Trauma wounds (skin tears, abrasions, lacerations)
  • Vascular wounds
  • Diabetic wounds
  • Surgical wounds

It is vital to differentiate partial- versus full-thickness wounds for a multitude of reasons, such as to understand how they heal, guide treatment, and ensure clear accurate documentation, to name a few.

What are Partial-Thickness Wounds?

Partial-thickness wounds are superficial.1 They extend only through the first or second layers of the skin (epidermis or dermis). The National Pressure Injury Advisory Panel (NPIAP) further describes superficial (stage 2) pressure injuries as partial-thickness loss of skin with the exposed dermis and a pink or red, moist wound bed.1 Epithelial tissue is commonly present and appears as light pink tissue, often lighter than the surrounding skin. This lighter tissue appearance occurs when the epidermis regenerates over the surface area of the wound. Alternatively, stage 2 pressure injuries may present as an intact or ruptured clear fluid-filled blister. Subcutaneous tissue, granulation tissue, slough, and eschar would not be present in a partial-thickness wound. Partial-thickness wounds may heal by regeneration. Common partial-thickness wounds that are not staged include1:

  • Medical adhesive-related skin injury (MARSI)
  • Traumatic wounds (skin tears or abrasions)
  • Moisture-associated skin damage (MASD)

What Are Full-Thickness Wounds?

Full-thickness wounds, as the name implies, are deep; they extend beyond the first 2 layers of the skin and may reveal subcutaneous (fatty) tissue, muscle, tendon, or even bone. The NPIAP further breaks down the definition of full-thickness skin loss (stage 3 and 4 pressure injuries) as when adipose fat is visible, granulation tissue and epibole (closed or rolled wound edges) are often present, and slough or eschar may be visible.1

The depth of tissue damage varies by anatomical location. For example, the depth of a stage 4 pressure injury on the nose or lateral malleolus may be less than that of a stage 4 sacral pressure injury. Undermining or tunneling (or both) could also be present in these wounds.1

Fascia, muscle, tendon, ligament cartilage, or bone may be present in a stage 4 pressure injury but not stage 3. However, slough, eschar, and granulation tissue may be found in either stage of full-thickness wounds.1 For full-thickness wounds in which the patient’s bone is exposed, clinicians should take even greater care to prevent infection since there is an increased risk of osteomyelitis or osteitis.2 Additionally, full-thickness wounds involve a multi-step process related to repair, including hemostasis (in acute wounds), inflammation, proliferation, and contraction in brief.

Partial- Versus Full-Thickness: A Comparison

Many key features that differentiate partial- versus full-thickness wounds are described above. Some of these include the presence of epithelial tissue, granulation, slough, and eschar. Epithelial tissue is commonly seen in partial-thickness wounds such as skin tears, abrasions, MASD, and superficial pressure injuries. This tissue presents as clean, viable, and pink or red. It should not be confused with granulation tissue, which is also sometimes deep pink but more often appears as red, bumpy, shiny tissue that is highly vascular.1 In addition, slough, eschar, and bruising are not present in partial-thickness wounds.

The changes that occur during aging may impact the healing process in both partial- and full-thickness wounds and sometimes may result in delayed wound healing. While differentiating between partial- and full-thickness wounds, one should keep in mind that acute and chronic wounds also respond differently, and therefore the presentation and healing picture may look different.

Conclusion

For treatment, documentation, and knowledge purposes, it is important to understand the differences between partial- and full-thickness tissue loss and how these variances impact the patient, the healing cascade, and the “future” of the wound. For example, scar tissue will not be as strong as regular tissue and therefore poses a higher risk for wound recurrence. Knowing the differences between partial-and full-thickness wounds not only aids in accurate documentation but also helps clinicians create unique and effective care plans.

References

  1. National Pressure Injury Advisory Panel (NPIAP). National Pressure Injury Advisory Panel (npiap.com). Accessed November 26, 2022.
  2. Zulkowski K. Wound Classification. Agency for Healthcare Research and Quality. Accessed January 5, 2023. https://www.ahrq.gov/sites/default/files/wysiwyg/professionals/systems/h...

About the Author

Holly is a board certified gerontological nurse and advanced practice wound, ostomy, and continence nurse specialist at VA Northeast Ohio Healthcare System in Cleveland, Ohio. She has a passion for education, teaching, and our veterans. Holly has been practicing in WOC nursing for approximately ten years. She has much experience with the long-term care population and chronic wounds as well as pressure injuries, diabetic ulcers, venous and arterial wounds, surgical wounds, radiation dermatitis, and wounds requiring advanced wound therapy for healing. Holly enjoys teaching new nurses about wound care and, most importantly, pressure injury prevention. She enjoys working with each patient to come up with an individualized plan of care based on their needs and overall medical situation. She values the importance of taking an interprofessional approach with wound care and prevention overall, and involves each member of the health care team as much as possible. She also values the significance of the support of leadership within her facility and the overall impact of great teamwork for positive outcomes.

The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, HMP Global, its affiliates, or subsidiary companies.

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