Hypertrophic Scar
Author: Rima Hussaini
Chief Editor: Dr Daniel Keith
Introduction
What are Hypertrophic Scars?
Hypertrophic scars are a type of scar that develops as part of the body’s natural healing process after damage to the dermis, such as from injury, surgery, or burns. They are characterized by excessive fibrous tissue formation, which results in a scar that is thicker, raised, and more prominent than usual. However, unlike keloid scars, hypertrophic scars remain confined to the boundaries of the original wound and do not spread into surrounding healthy tissue.
Key Features of Hypertrophic Scars?
Appearance: Thickened, raised, and often red or pink in colour during their early stages.
Location: Remains within the limits of the original wound or incision.
Causes:
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Tension on the healing wound (e.g., areas of high skin movement like joints or shoulders).
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Prolonged inflammation or delayed wound healing.
Prognosis:
The scar tissue is more likely to diminish in thickness and size, becoming less raised or pronounced. Hypertrophic scars may resolve over time compared to keloids, often becoming flatter and less noticeable within months to a few years.
Macroscopic Appearance
The macroscopic appearance of hypertrophic scars can be described as follows:
Colour:
Typically pink to red in colour, especially in the early stages. The redness reflects the increased blood flow and activity in the scar tissue during healing. In skin types IV – VI, the colour may appear more pigmented.
Shape and Surface:
Slightly raised above the surrounding skin or, in some cases, flat. The scar is confined to the boundaries of the original wound and does not extend into the surrounding skin (unlike keloids).
Texture and Sensation:
The scar can feel firm to the touch. It is often associated with discomfort or itchiness, particularly during the active phases of healing.
Timing:
They typically develop within weeks of the initial injury or surgery.
Common Locations:
Hypertrophic scars are most likely to occur in areas where the skin experiences high tension or frequent movement, such as shoulders, chest, upper arms and cheeks.
Figure 1a: Fitzpatrick skin type 6 - Hypertrophic scar on the right cheek
Figure 1b: Fitzpatrick skin type 3 - Hypertrophic scar on the back
Figure 1c: Fitzpatrick skin type 1 - hypertrophic scar on the chin and neck following a burn injury
Dermoscopic Appearance
White Scar-Like Areas:
These appear as irregular, shiny white areas corresponding to dense collagen deposition in the dermis, a hallmark of scar tissue formation.
Vasculature:
Vascularisation is often not observed however thin, linear or arborizing blood can be seen. This vascularity reflects the increased blood supply during the active phase of scar remodelling, particularly in larger surface areas, such as in burns.
Colour:
Hypertrophic scars tend to present a brown colour under dermoscopy due to the stimulation of melanocytes. The brown is usually patchy with white areas and pink.
Figure 1b: Fitzpatrick skin type 6 - dermoscopic view of a hypertrophic scar showing brown pigment and surrounding white areas with no vascular structures apparent.
Figure 1b (annotated): Fitzpatrick skin type 6 - dermoscopic view of a hypertrophic scar showing brown (red circle) pigment and surrounding white areas (blue circle) with no vascular structures apparent.
Figure 2b: Skin type 3 - Dermoscopic hypertrophic scar with brown pigment and white pigment with no distinct pattern and little vascular structures. The Vascular structures are present are less visible and linear
Figure 2b (annotated): Skin type 3 - Dermoscopic hypertrophic scar with brown pigment (red circle) and white pigment (blue circle) with no distinct pattern and minimal vascular structures (purple arrows). The Vascular structures are present are less visible and linear
Figure 3b: Fitzpatrick Skin type 1 - Dermoscopic hypertrophic scar brown pigment and white areas. Vascular structures are present and are linear and arborising.
Figure 3b (annotated): Fitzpatrick Skin type 1 - Dermoscopic hypertrophic scar with brown pigment (red circle) and white areas (blue circle). Vascular structures are present and are linear (purple arrows) and arborising (yellow arrows).
Differentiating between Hypertrophic Scars and Basal Cell Carcinoma
