A hypertrophic scar is a thickened, raised mark that forms when the body produces excessive collagen during wound healing. A primary characteristic is that the scar remains confined to the boundaries of the original injury. While not medically dangerous, these scars can cause discomfort or be a cosmetic concern.
Identifying Hypertrophic Scars
Hypertrophic scars appear as firm, raised tissue that can be pink, red, or darker than the surrounding skin, developing within weeks to months after an injury. They may cause symptoms like tenderness, itching, or a feeling of tightness over the affected area. The scar’s appearance will mirror the shape of the original cut, burn, or incision.
The defining feature of a hypertrophic scar is that it stays within the confines of the original wound. This is the main difference between it and a keloid scar, which grows aggressively beyond the injury’s borders into healthy skin. While both are raised and result from excess collagen, keloids can become large and irregular, while hypertrophic scars tend to stabilize and may flatten over time.
Causes and Risk Factors
The formation of a hypertrophic scar results from a disruption in the wound healing process where cells called fibroblasts become overactive. This leads to an excessive deposit of collagen, which builds up and creates the scar’s raised, thick texture. An imbalance between collagen production and breakdown is the underlying biological trigger.
Several factors can increase the likelihood of developing this type of scar. Wounds located on areas of the body with high skin tension are particularly susceptible because constant movement places stress on the healing tissue. Common sites include:
- The chest
- Shoulders
- The upper back
- Joints like elbows and knees
Deep traumatic wounds, surgical incisions, and severe burns are also frequent precursors. Younger people, between the ages of 10 and 30, have a more robust healing response that can increase susceptibility. A prolonged inflammatory phase during healing, due to infection or delayed wound closure, can also trigger the overproduction of collagen. Some individuals may also have a genetic predisposition that makes them more prone to forming these types of scars.
Wound Care and Prevention
After an injury, specific wound care practices can minimize the chances of a hypertrophic scar developing. The goal is to support a stable and uninterrupted healing environment to prevent the overproduction of collagen. One of the most common preventative measures is the use of silicone-based products, such as gels or sheets, applied directly to the wound once it has closed.
Silicone therapy works by hydrating the scar tissue and regulating factors that control fibroblast activity. This moisture helps soften the tissue and can reduce the final thickness and color of the scar. For best results, silicone products should be used consistently for several weeks to months.
Another preventative strategy is pressure therapy, often using specialized garments, which is frequently used for extensive scars from burns. The constant pressure on the healing area is believed to reduce blood flow to the scar, limiting the nutrients available to overactive fibroblasts and decreasing collagen synthesis. Combining pressure therapy with silicone may offer additional benefits.
Medical Treatment Options
For established hypertrophic scars, several medical treatments can reduce their size, improve their texture, and alleviate symptoms. A healthcare provider may recommend one or more of the following options:
- Corticosteroid Injections: These are administered directly into the scar tissue to decrease inflammation, soften the scar, and interfere with collagen synthesis. Multiple injections spaced a few weeks apart are often needed.
- Other Injected Medications: Substances like 5-fluorouracil (5-FU), which inhibits cell growth, can be injected to reduce the proliferation of fibroblasts. This treatment may be used alone or combined with corticosteroids to enhance the outcome.
- Laser and Light Therapy: Pulsed-dye or Nd:YAG lasers target blood vessels within the scar tissue. This process can reduce the scar’s reddish appearance and improve its texture and flexibility.
- Cryotherapy: This method involves using liquid nitrogen to freeze the scar tissue from the inside. The freezing process destroys the excess cells, helping to flatten the scar over time.
- Surgical Revision: This procedure involves excising the scar tissue and re-closing the wound to create a less noticeable scar. However, there is a risk of recurrence, so surgery is frequently combined with other treatments like post-operative corticosteroid injections.