Wound Tissue Types in Chronic Wounds

Introduction

Chronic wounds place a tremendous strain on the healthcare system. It is critical to perform an accurate wound assessment in addition to determining the cause of the wound. The color, consistency, and texture of the wound bed tissue can be used to determine the correct wound etiology and tissue types. Tissue type percentages should be 100% during the wound assessment. Correctly identifying tissue types is essential in wound management.

Tissue Types

Epithelial

The epithelium is a pale pink, pearl-like tissue that forms on top of granulation tissue in full thickness wounds. Epithelial cells migrate outward from the wound margins, traveling across the wound bed to the point of closure. Once the epithelium is formed, it gradually becomes stronger. This process is called epithelialization and takes place in partial-thickness wounds.

Granulation

The proliferative phase is when granulation tissue is formed. Granulation that is healthy is pink or red in hue and has an irregular mounded texture. Capillary loops or granulation buds form these mounds. Dark dark granulation is indicative of ischemia, inadequate perfusion, or infection. When myofibroblasts assist in wound contraction and epithelial cells resurface across the wound bed, the proliferative phase will come to a close. Healthy granulation tissue is pink or red in color and is an excellent indicator of healing.

Slough

Slough is non-viable or devitalized tissue that may be fibrinous, sticky, stringy, or thickened. The color varies between yellow and tan. Slough houses harmful organisms, raises the risk of infection, and impairs healing, making debridement treatments necessary. Exposure to live tissue accelerates the healing process.

Hypergranulation

Hypergranulation refers to excessive granulation or “proud flesh.” Above the regular wound bed surface, the wound tissue will be visible. Hypergranulation is defined by the appearance of bright red or dark pink flesh that is smooth, bumpy, or granular and extends beyond the stoma opening’s surface.

Scab

The term “scab” refers to a crust that has formed as a result of blood or exudate coagulation. Scabs are found on wounds that are superficial or partial in-depth. A scab is a rusty brown, crusty crust that appears within 24 hours of damage on any wounded surface of the skin. The outside surface of this blood clot dries to produce a rusty brown crust known as a scab, which acts as a cap over the underlying healing tissues. Scabs normally remain firmly in place until the underlying skin is restored and new skin cells emerge, at which point they come off spontaneously.

Eschar

The term “eschar” is NOT synonymous with “scab.” Eschar is decomposing tissue that is discovered in a full-thickness wound. Eschar may develop as a result of a burn injury, gangrenous ulcer, fungal infection, necrotizing fasciitis, spotted fevers, or anthrax exposure. The current standard of care recommendations recommends against removing stable undamaged (dry, adherent, and without erythema or fluctuance) eschar on the heels. Blood flow is inadequate in the tissue underneath the eschar, making the lesion prone to infection. By preventing bacteria from accessing the wound, the eschar acts as a natural barrier to infection. If the eschar becomes unstable (wet, draining, loose, boggy, edematous, or red), it should be debrided in accordance with the clinic’s or facility’s policy.

Disclaimer

The views and opinions stated in this blog are exclusively those of the author and do not reflect iWound, its affiliates, or partner companies.

References

Schultz GS, Sibbald RG, Falanga V, Ayello EA, Dowsett C, Harding K, Romanelli M, Stacey MC, Teot L, Vanscheidt W. Wound bed preparation: a systematic approach to wound management. Wound Repair Regen. 2003 Mar;11 Suppl 1:S1-28. doi: 10.1046/j.1524-475x.11.s2.1.x. PMID: 12654015.

Falanga V, Phillips TJ, Harding KG, Moy RL, Peerson LJ, eds. Text atlas of wound management. London: Martin Dunitz, 2000

Grey, J. E., Enoch, S., & Harding, K. G. (2006). Wound assessment. BMJ (Clinical research ed.), 332(7536), 285–288. https://doi.org/10.1136/bmj.332.7536.285

Carver. C. Knowing the Difference Between Scab and Eschar. WoundSource.com. 2016. Available at: http://www.woundsource.com/blog/knowing-difference-between-scabs-and-eschar Accessed March 20, 2022.

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