A scar that grows beyond the boundaries of the original wound is called a keloid scar whereas a scar that is raised above the skin level but grows within the boundaries of the original wound is known as a hypertrophic scar. As their definitions state, keloid scar grows out of the boundaries of the original wound but a hypertrophic scar grows within the boundaries of the original wound. This is the key difference between keloid scar and hypertrophic scar.
CONTENTS
1. Overview and Key Difference
2. What is a Keloid Scar
3. What is a Hypertrophic Scar
4. Similarities Between Keloid and Hypertrophic Scar
5. Side by Side Comparison – Keloid vs Hypertrophic Scar in Tabular Form
6. Summary
What is a Keloid Scar?
When the epithelium is damaged either due to tissue injury or due to the loss of integrity of the epithelium cells, the repair mechanisms are spontaneously activated. If the damage is minimal, the repairing happens through tissue regeneration. But in case of severe injury or repeated exposure to an injurious agent, the damaged tissues are inflamed. Some of the cytokines such as IL13 and TGF beta released by the inflamed cells stimulate the recruitment of fibroblasts, which later differentiate into myofibroblasts. The end result is the formation of a fibrous tissue mass. This process is known as fibrosis.
Figure 01: Keloid Scar
Keloid scars are due to the excessive formation of these scar tissues. When the scar extends beyond the boundaries of the original wound and does not regress, it is called a keloid scar.
What is a Hypertrophic Scar?
Hypertrophic scars are also a result of the excessive formation of collagen fibers during wound healing. Although these scars are raised above the skin level, they do not grow beyond the boundaries of the original wound.
Figure 02: Hypertrophic Scar
Treatment of Keloid and Hypertrophic Scars
- Surgical excision
- Cryotherapy
- Compression therapy
- Radiation therapy
- Occlusive Dressings
- Intralesional corticosteroid injections
What is the Similarity Between Keloid and Hypertrophic Scar?
- Both types of scars are due to the excessive production of collagen fibers during wound healing.
What is the Difference Between Keloid and Hypertrophic Scar?
Keloid vs Hypertrophic Scar |
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| A scar that grows beyond the boundaries of the original wound is called a keloid scar. | A scar that is raised above the skin level but grows within the boundaries of the original wound is known as a hypertrophic scar. |
Summary – Keloid vs Hypertrophic Scar
A scar that grows beyond the boundaries of the original wound is called a keloid scar and a scar that is raised above the skin level but grows within the boundaries of the original wound is known as a hypertrophic scar. Unlike hypertrophic scars that grow within the limits of the original wound, a keloid scar grows beyond the boundaries of the original wound. This is the main difference between keloid scar and hypertrophic scar.
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References:
1. Kumar, Vinay, Stanley Leonard Robbins, Ramzi S. Cotran, Abul K. Abbas, and Nelson Fausto. Robbins and Cotran pathologic basis of disease. 9th ed. Philadelphia, Pa: Elsevier Saunders, 2010. Print.
Image Courtesy:
1. “Keloid” By Michael Rodger – Own work (CC BY 3.0) via Commons Wikimedia
2. “WhiteTailedSpiderBite” By Ezytyper at English Wikipedia – Transferred from en.wikipedia to Commons. (Public Domain) via Commons Wikimedia