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What to do with too much of a good thing
By Liza Ovington, PhD, CWS
President, Ovington & Associates
Fort Lauderdale, FL
The wound healing process has been described as consisting of three overlapping phases: inflammation, proliferation, and maturation. Each phase is characterized by specific cells and biochemical processes. In the inflammatory phase, platelets act to achieve hemostasis while white blood cells fight infection. In the proliferative phase, the wound defect fills with granulation tissue and covers over with epithelial tissue. In the maturation phase, the wound slowly regains tensile strength through collagen remodeling.
Wound care professionals are familiar with the appearance of healthy granulation tissue, which should be beefy red and granular or "cobblestone" in appearance. Both the color and texture of granulation tissue are due to newly formed capillary loops. Granulation tissue also contains large numbers of fibroblasts, which are actively synthesizing collagen and other extracellular matrix molecules such as glycosaminoglycans and hyaluronic acid. Granulation tissue in the wound is considered a positive sign and a necessary component of wound healing.
However, there are instances when too much granulation occurs. Rather than simply filling up the wound defect, the tissue exceeds the edges of the wound or mounds up above the level of the surrounding intact skin. This condition is known as hypergranulation. Other terms for hypergranulation include exuberant granulation and "proud flesh." Certain individuals may be predisposed to hyperplasia and tend to develop hypergranulation or hypertrophic scars. There also have been suggestions that fully occlusive dressings such as some hydrocolloid dressings may promote a hypergranular response in certain cases.1,2 Low wound oxygen tension created by the occlusive dressing is thought to accelerate the deposition of granulation tissue by fibroblasts.3
An excess of granulation tissue in a wound can actually delay healing because epithelial cells cannot "climb" over it and are therefore arrested at the wound edge. So, while some granulation tissue is a good thing, it is possible to have too much of a good thing. When hypergranulation is encountered, it must be removed or flattened out so the epithelial tissue can subsequently resurface the wound and restore barrier function.
There are very little data in the literature concerning methods for addressing hypergranulation in human wounds. However, hypergranulation or proud flesh is rather common in canine and equine wounds, and there are a number of references concerning its management in veterinary journals.4,5 Veterinary management methods include chemical cautery, cryogenic surgery, surgical resection, topical steroids, or leaving the wound open to air. In the human population, hypergranulation may be dealt with in a number of similar ways.
Chemical cautery with a silver nitrate pencil is perhaps the most common method of removing excess granulation tissue. When silver nitrate contacts the superficial exposed tissues, it causes them to necrose almost immediately. The necrosed layer may then be wiped off gently. Contact of silver nitrate with intact skin will cause the skin to darken but not necrose. Use of silver nitrate should be undertaken with caution and an appropriate protocol.
Because granulation tissue is by nature very delicate, it also has been suggested that the excess can be removed by wiping a gauze sponge around the wound edges with moderate pressure.3
Foam dressings can reduce hypergranulation
A less traumatic approach to managing hypergranulation tissue caused or exacerbated by occlusion is switching from the occlusive dressing to an absorbent, semiocclusive dressing such as a polyurethane foam. This approach was verified in a small clinical trial of 10 patients, which documented a significant decrease in the height of hypergranulation tissue at a two-week time point after institution of the foam dressing.6 Additional methods for reducing excess granulation include the use of topical corticosteroid creams and surgical removal.
An important caveat to the management of hypergranulation bears mentioning. It may be wise to rule out malignancy in certain chronic wounds with excessive granulation. Clinicians at the University of Miami dermatology department have documented multiple cases of hypergranulation in venous ulcers that were revealed upon biopsy to be basal cell carcinoma.7 It was noted that in all of the five cases described, the granulation tissue exceeded the margins of the ulcer and appeared to be healthy.
References
1. Thomas S. "Hydrocolloid Dressings." In: Wound Management and Dressings. London: Pharmaceutical Press; 1990, pp. 55-61.
2. Morgan PW, Binnington AG, Miller CW, et al. The effect of occlusive and semi-occlusive dressing on the healing of acute full thickness skin wounds on the forelimbs of dogs. Vet Surg 1994; 23:494-502.
3. Feedar JA. "Clinical Management of Chronic Wounds." In: Wound Healing: Alternatives in Management. Philadelphia: FA Davis and Co.; 1995, pp. 137-185.
4. Bertone AL. Management of exuberant granulation tissue. Vet Clin North Am Equine Pract 1989; 5:551-562.
5. Bertone AL, Sullis KE, Stashak TS, Norrdin RW. Effect of wound location and the use of topical collagen gel on exuberant granulation tissue formation and wound healing in the horse and pony. Am J Vet Res 1985; 46:1,438-1,444.
6. Harris A, Rolstad BS. Hypergranulation tissue: a nontraumatic method of management. Ostomy Wound Management 1994; 40:20-22, 24, 26-30.
7. Harris B, Eaglstein WH, Falanga V. Basal cell carcinoma arising in venous ulcers and mimicking granulation tissue. J Dermatol Surg Oncol 1993; 19:150-152.
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