Hypertrophic Scar: Symptoms, Types, Causes and Treatment

Hypertrophic scars are a common yet complex outcome of wound healing, often causing not only cosmetic concerns but also significant physical and psychological distress. They can develop after injuries, surgeries, or burns, and are characterized by raised, thickened areas of skin that may be painful or itchy. Understanding the symptoms, types, causes, and treatments of hypertrophic scars is vital for anyone affected or at risk. This article provides an in-depth look, synthesizing the latest research to guide patients, caregivers, and clinicians.

Symptoms of Hypertrophic Scar

Hypertrophic scars don't just affect appearance—they can impact daily life and well-being. Recognizing their symptoms early can make a crucial difference in management and outcomes.

Symptom	Description	Impact	Source(s)
Thickening	Raised, firm tissue above skin surface	Cosmetic, tactile	1, 2, 5
Redness	Increased vascularity, pink-red coloration	Visible change	1, 5
Itching	Persistent pruritus, sometimes severe	Discomfort	1, 2
Pain	Tenderness or soreness in the scar region	Functional impact	1, 2, 5
Contracture	Tightening and shortening of skin	Limits movement	2, 5
Pigmentation	Hyper- or hypopigmentation	Color mismatch	1, 2
Stiffness	Reduced pliability of skin	Affects mobility	1, 5

Table 1: Key Symptoms

Understanding the Symptoms

Thickening and Texture Changes

One of the hallmark signs of hypertrophic scars is their thickness. Unlike flat, mature scars, hypertrophic scars stand out as firm, raised tissue, often measuring several millimeters above the surface of the surrounding skin. This is due to excessive collagen deposition during the healing process, creating a dense and fibrous texture that’s easily felt to the touch 1, 5.

Redness and Pigmentation

Hypertrophic scars frequently appear red or pink, especially in the early stages. This coloration is linked to increased blood supply (vascularity) in the healing tissue. Over time, scars may also become darker (hyperpigmented) or lighter (hypopigmented) than the surrounding skin, leading to visible color contrast 1, 2.

Itching and Pain

A significant number of people with hypertrophic scars report bothersome itching (pruritus) and pain. In one study, over 40% of patients experienced these symptoms just one month after surgery 1. Itching can be persistent and distressing, while pain may be sharp, aching, or even burning, particularly if the scar is stretched or compressed.

Contracture and Reduced Mobility

When hypertrophic scars form over joints or large areas, they can contract, pulling the skin tight and limiting the range of motion. This is especially common after burns and can lead to serious functional impairment if untreated 2, 5.

Stiffness and Loss of Pliability

Compared to normal skin, hypertrophic scars are less flexible. This stiffness can make the area feel tight or uncomfortable, particularly during movement 1.

Types of Hypertrophic Scar

Not all hypertrophic scars are the same. They can differ in appearance, location, and behavior, which influences their management.

Type	Defining Feature	Typical Location	Source(s)
Linear	Follows surgical/incision	Surgical sites	3, 12
Widespread	Large, irregular area	Burns, trauma	5, 6
Early/Immature	Red, raised, active	Any wound site	5, 12
Mature	Flatter, paler, less active	Healed scars	5, 12
Contracture Scar	Scar with functional loss	Joints, flexion areas	2, 5

Table 2: Hypertrophic Scar Types

Exploring the Different Types

Linear Hypertrophic Scars

These scars usually develop along surgical incisions or lacerations. They are typically narrow, raised, and confined to the wound margin. Linear scars may improve over time, especially with early intervention 3, 12.

Widespread Hypertrophic Scars

Common after burns or major trauma, these scars cover larger, irregular areas. They are more prone to complications like contractures and pigment changes, particularly when healing is delayed or complicated by infection 5, 6.

Early (Immature) vs. Mature Scars

• Early/Immature Hypertrophic Scars: These are actively forming, appearing red, raised, and often itchy or painful. They have increased vascularity and cellular activity, making them more responsive to interventions 5.
• Mature Hypertrophic Scars: Over months, scars may flatten and fade, with reduced redness and symptoms. However, they can still be problematic, especially if contractures developed during the active phase 5, 12.

Contracture Scars

When a hypertrophic scar forms across a joint or a mobile area, it may pull the skin tight, causing restricted movement—these are known as contracture scars. They are particularly challenging after burns and can severely impact function 2, 5.

Causes of Hypertrophic Scar

Understanding why hypertrophic scars develop is key to prevention and effective treatment. Multiple factors, from biological processes to patient-specific risks, play a role.

Cause	Mechanism/Trigger	Risk Increase	Source(s)
Deep Dermal Injury	Trauma, burns, surgery	High	7, 10
Inflammation	Chronic wound inflammation	Significant	7, 8
Excessive Collagen	Overactive fibroblasts	High	3, 10
Genetic Predisposition	Family or ethnic background	Variable	1, 7, 9
Mechanical Tension	Skin stretch during healing	Increased	9, 7
Infection	Bacterial colonization	Increased	9, 8
Age (Younger)	Children, young adults	Increased	9
Hormonal/Cellular Factors	Growth/cytokine imbalance	Increased	3, 4, 10

Table 3: Causes and Risk Factors

The Complex Pathways of Hypertrophic Scar Formation

Deep Dermal Injury

Hypertrophic scars only develop when a wound extends into the deep layers of the skin, particularly the reticular dermis. Superficial wounds rarely result in such scarring 7, 10.

Persistent Inflammation

Chronic inflammation in the wound area is a key driver. Proinflammatory cytokines—such as interleukins and tumor necrosis factor alpha—are upregulated, keeping the healing process in an "active" state and leading to excessive tissue growth 7, 8.

Collagen Overproduction

A central feature is the overproduction and abnormal arrangement of collagen by activated fibroblasts. This leads to the raised, firm texture of hypertrophic scars 3, 10.

Genetic and Ethnic Factors

Some individuals and populations are more prone to hypertrophic scarring. For example, studies show a higher prevalence in non-Caucasian groups, such as the Chinese population, and familial tendencies suggest a genetic component 1, 9.

Mechanical Tension

Wounds under mechanical tension—such as those in high-movement areas—are more likely to develop hypertrophic scars. Stretching stimulates fibroblast activity and collagen production 9, 7.

Infection and Delayed Healing

Infection prolongs inflammation and delays wound closure, both of which increase the risk of hypertrophic scarring 9, 8.

Age and Hormonal Factors

Younger individuals, especially children and young adults, are at higher risk, possibly due to more active skin healing. Hormonal and cellular mediators, including transforming growth factor-beta (TGF-β), platelet-derived growth factor (PDGF), and components of the renin-angiotensin system, also contribute to abnormal scar formation 3, 4, 10.

Treatment of Hypertrophic Scar

Although challenging, hypertrophic scars can be managed with a variety of treatments. The best outcomes often result from early, tailored interventions that address both the vascular and collagen components of the scar.

Treatment	Approach/Mechanism	Use Stage	Source(s)
Silicone Gel/Sheeting	Occlusion, hydration	Early, prevention	12, 13
Pressure Therapy	Reduces blood flow/collagen	Early, burns	12, 13
Steroid Injections	Anti-inflammatory, reduces collagen	Active scars	7, 12
Laser Therapy	Targets vessels/collagen	Vascular/collagen	5, 12
Cryotherapy	Freezes scar tissue	Small, raised scars	7, 12
Surgery	Excision of scar tissue	Severe cases	3, 12
Emerging Therapies	E.g., PDT, biologics	Deep/Resistant scars	14, 4, 5

Table 4: Treatment Approaches

Navigating Treatment Options

First-Line and Nonsurgical Therapies

• Silicone Gel/Sheeting: Widely used for both prevention and treatment, silicone maintains hydration, reduces inflammation, and flattens scars. It's non-invasive and easy to use 12, 13.
• Pressure Therapy: Especially effective for burn scars, this involves wearing custom-fitted garments that apply continuous pressure, reducing blood supply and collagen synthesis 12, 13.
• Topical Agents: Onion extract, vitamin E, and polyurethane dressings are sometimes used, though evidence for their effectiveness varies 13.

Steroid and Medication-Based Interventions

• Intralesional Steroids: Corticosteroid injections reduce inflammation and fibroblast activity, leading to flatter, softer scars. These are often first-line for symptomatic or rapidly growing scars 7, 12.
• Other Medications: Bleomycin, 5-fluorouracil, and newer agents like imiquimod can be used in cases resistant to standard treatments 7, 12.

Physical and Light-Based Therapies

• Laser Therapy: Lasers such as pulsed dye and fractional CO2 target blood vessels and collagen, improving scar color and texture. Selection depends on the scar's characteristics (vascular- or collagen-dominant) 5, 12.
• Cryotherapy: Used for smaller scars, freezing can reduce scar volume but may risk pigment changes 7, 12.

Surgical and Advanced Treatments

• Surgical Excision: Reserved for severe or functionally limiting scars, especially contractures. Surgery is often combined with adjuvant therapies to reduce recurrence 3, 12.
• Emerging Therapies: Photodynamic therapy (PDT), biologics targeting specific growth factors, and agents modulating the renin-angiotensin system show promise for deep or resistant hypertrophic scars 14, 4, 5.

Matching Treatment to Scar Stage

Recent research suggests that tailoring therapy to the dominant features—vascularity in early scars, collagen in mature scars—can yield better outcomes. For example:

• Early, red scars: Vascular-targeted treatments (laser, pressure).
• Mature, thick scars: Collagen-targeted therapies (CO2 laser, collagenase) 5.

Conclusion

Hypertrophic scars are a frequent and challenging consequence of wound healing, marked by visible, symptomatic, and sometimes disabling changes in the skin. Understanding their symptoms, types, causes, and treatments empowers patients and clinicians alike to pursue timely and effective management.

Key takeaways:

• Symptoms include thickening, redness, itching, pain, contracture, and pigment changes, significantly impacting quality of life 1, 2, 5.
• Types range from linear surgical scars to widespread burns, with distinctions between early/immature and mature scars, as well as contracture forms 3, 5, 12.
• Causes are multifactorial, involving deep dermal injury, chronic inflammation, excessive collagen, genetic predisposition, mechanical tension, infection, and more 1, 7, 9, 10.
• Treatment options are diverse, from silicone and pressure therapy to steroids, lasers, surgery, and emerging biological agents. Tailoring therapy to the scar's stage and features is crucial for optimal results 5, 12, 14.

With ongoing research and evolving therapies, the outlook for individuals with hypertrophic scars continues to improve. Early recognition, personalized care, and a holistic approach remain at the heart of successful scar management.