A hypertrophic scar is a thick, raised scar that forms when the body produces too much collagen during the healing process. These scars can develop after burns, surgical procedures, or other forms of skin trauma, and while they may gradually improve over time, understanding their nature and available treatments can help people manage both their appearance and any discomfort they cause.

What Happens When a Hypertrophic Scar Forms

When skin is injured deeply enough to affect the dermis—the thick layer of skin below the surface—the body responds by producing collagen, a protein that helps repair damaged tissue. Collagen is naturally thicker and less flexible than regular skin. In most cases, this repair process creates a flat scar that blends relatively well with surrounding skin. However, sometimes the body’s healing response becomes overactive, producing extra collagen that accumulates within the boundaries of the original wound. This excessive tissue buildup creates a raised, firm scar known as a hypertrophic scar.^[1]

The term “hypertrophic” refers to the enlarged or overgrown nature of the scar tissue. Unlike normal scars that remain relatively flat, hypertrophic scars rise above the surrounding skin surface and feel thicker to the touch. The development of these scars represents an abnormal wound healing response, where the balance between collagen production and breakdown becomes disrupted.^[3]

How Hypertrophic Scars Differ from Keloid Scars

People often confuse hypertrophic scars with keloid scars because both types appear raised and firm. However, there is a crucial difference in how these scars behave. Hypertrophic scars remain confined within the original wound area. They do not spread beyond the boundaries where the injury occurred. In contrast, keloid scars grow beyond the original wound site, sometimes becoming much larger than the initial injury.^[1]

The color and timing of development also differ between these scar types. Hypertrophic scars typically appear pink to red and develop within one to two months after an injury. Keloid scars tend to be darker, ranging from red to purple, and may take several months or even years to appear. Another important distinction is that hypertrophic scars often become less noticeable over time and may improve without treatment, while keloid scars never go away on their own and require intervention.^[1]

When examined under a microscope, the internal structure of these scars reveals additional differences. In hypertrophic scars, collagen fibers arrange themselves in a somewhat organized pattern, running parallel to the skin’s surface. Keloid scars show a disorganized, random arrangement of collagen fibers with more blood vessels present. These structural differences help medical professionals distinguish between the two types of scarring.^[1]

Where Hypertrophic Scars Commonly Appear

Hypertrophic scars develop most frequently in areas where skin experiences constant tension or stretching. The back, chest, shoulders, upper arms, and elbows are particularly susceptible locations. These areas of the body have what doctors call “taut skin,” meaning the skin is naturally pulled tight across underlying structures. Joints, where the skin regularly bends and stretches with movement, also commonly develop hypertrophic scars.^[1]

Despite this pattern, hypertrophic scars can potentially form anywhere on the body where skin injury has occurred. The location matters because areas with more skin tension tend to experience more pronounced scarring. This is why injuries over joints or on the chest often result in more noticeable raised scars compared to injuries in areas where skin moves more freely.^[1]

Common Causes and Triggers

Hypertrophic scars arise from various types of skin damage that penetrate deep enough to require significant healing. Burn injuries, particularly second and third-degree burns, frequently lead to hypertrophic scarring. When burns destroy multiple layers of skin, the extensive healing process often triggers excessive collagen production.^[1]

Surgical incisions represent another common cause. After surgery, the body works to close and heal the surgical wound, sometimes overproducing scar tissue in the process. Accidental trauma from cuts, lacerations, or other injuries can also result in hypertrophic scars, especially when the wound is deep or takes a long time to heal.^[1]

Inflammation plays a significant role in hypertrophic scar formation. When a wound becomes inflamed or infected, the prolonged inflammatory response can trigger excessive collagen production. Even seemingly minor skin problems like severe acne, chickenpox, or insect bites can develop into hypertrophic scars if inflammation persists or if the affected area is repeatedly irritated.^[3]

Body piercings and tattoos may also lead to hypertrophic scarring. These procedures intentionally wound the skin, and in some individuals, the healing process goes awry, producing raised scars around the piercing or tattoo site.^[4]

Who Is at Higher Risk

While hypertrophic scars can develop in anyone, certain factors increase the likelihood of their formation. Age plays a role, with people between 10 and 30 years old showing higher rates of hypertrophic scarring. This increased risk may relate to the fact that younger skin produces collagen more rapidly and has greater elasticity, potentially contributing to more vigorous scar formation.^[17]

The nature of the wound itself affects scarring risk. Wounds that become infected or remain inflamed for extended periods are more likely to develop into hypertrophic scars. Similarly, wounds subjected to significant tension or movement—such as those crossing joints—face higher risk because constant pulling on the healing tissue stimulates excessive collagen production.^[4]

Some people may have an inherited tendency toward developing hypertrophic scars, though this genetic predisposition is not as strong as it is for keloid formation. Certain medical conditions that affect tissue formation and healing may also influence scarring patterns. People with Ehlers-Danlos syndrome, a group of disorders affecting connective tissues, may be more prone to developing hypertrophic scars.^[4]

Symptoms and How They Affect Daily Life

Hypertrophic scars are readily visible as raised, thick areas of skin. They typically appear pink or red in color, especially in their early stages. The texture feels firm and different from surrounding normal skin. Beyond these cosmetic changes, hypertrophic scars often cause physical symptoms that can significantly impact quality of life.^[2]

Itching is one of the most common and bothersome symptoms. The persistent urge to scratch can be intense and difficult to resist, yet scratching can damage the healing tissue and potentially worsen the scar. Many people with hypertrophic scars also experience pain or unusual sensitivity in the scarred area. The scar may feel tender to touch or produce a burning sensation.^[3]

When hypertrophic scars form near or across joints, they can restrict movement. Because scar tissue is less flexible than normal skin, it doesn’t stretch as easily. This limitation can make it difficult to fully bend or extend an affected joint, potentially interfering with everyday activities. A scar across the elbow, for example, might make it uncomfortable to fully straighten the arm, while a scar on the knee could affect walking or climbing stairs.^[2]

The appearance of hypertrophic scars can also take an emotional toll. Visible scars, particularly on the face, neck, or hands, may cause self-consciousness and affect social interactions. Some people report feeling anxious in social situations, experiencing reduced self-confidence, or dealing with sadness and frustration related to their scars.^[21]

Natural Changes Over Time

One encouraging aspect of hypertrophic scars is their tendency to improve spontaneously. Scar formation follows several phases of healing and maturation. Initially, during the first few weeks after injury, inflammation dominates as the body clears away damaged tissue and begins repair. Next comes a proliferation phase lasting about two weeks, during which cells multiply rapidly and produce new tissue.^[9]

The final maturation or remodeling phase can last from several weeks to multiple years. During this time, the body gradually reorganizes scar tissue, breaking down excess collagen and refining the scar’s structure. Hypertrophic scars typically develop within one to two months after injury and may continue to enlarge and redden for about four to six months. After this active growth period, the scar usually begins to soften and flatten.^[9]

It can take up to a year—sometimes longer—for a hypertrophic scar to fully mature. During this time, the scar typically becomes smaller, paler, softer, and less noticeable. The red or pink color gradually fades toward a shade closer to the surrounding skin. While the scar may never completely disappear, many hypertrophic scars improve dramatically on their own without any treatment. In fact, most doctors recommend waiting several months to a year before pursuing active treatment, giving the body’s natural remodeling process time to work.^[7]

Prevention Strategies

Preventing hypertrophic scars starts with proper wound care and management during the healing process. When surgery is planned, working with a skilled surgeon who can close wounds carefully makes a significant difference. Surgical techniques that minimize tension on the wound, align skin edges precisely, and follow natural skin creases all help reduce the risk of excessive scarring.^[21]

For people known to develop hypertrophic scars, doctors may recommend preventive measures even before scarring begins. Applying silicone gel sheets or silicone-based products immediately after a wound closes can help prevent excessive scar formation. These products appear to work by keeping the healing skin moist and creating a specific environment that discourages overactive collagen production.^[9]

Keeping wounds clean and protecting them from infection is crucial. Infections prolong inflammation and increase the likelihood of hypertrophic scarring. Following proper wound care instructions, keeping the area clean, and watching for signs of infection all contribute to better healing outcomes.^[8]

For people undergoing elective procedures like piercings or tattoos, informing the practitioner about any history of problematic scarring allows for extra precautions. Some people at high risk may choose to avoid unnecessary procedures that could trigger scar formation in vulnerable areas.^[9]

Protecting healing wounds from sun exposure helps prevent darkening and potentially reduces scarring severity. Using sunscreen with an SPF of at least 30 on healing wounds and new scars shields the vulnerable tissue from ultraviolet damage that can worsen scar appearance.^[20]

How the Body’s Normal Healing Process Goes Wrong

Understanding what happens at the cellular level helps explain why some wounds develop into hypertrophic scars. Normal wound healing requires careful coordination between different types of cells and chemical signals. Specialized cells called fibroblasts play a central role by producing collagen and other proteins that form the structural framework of new tissue.^[12]

In normal healing, fibroblasts respond to chemical signals telling them when to start and stop making collagen. The production of new collagen must balance with the breakdown of old collagen. When this balance is maintained, wounds heal with minimal scarring. However, in hypertrophic scar formation, this regulatory system malfunctions.^[3]

During hypertrophic scar development, fibroblasts become overactive and produce excessive amounts of collagen over extended periods. Certain forms of fibroblasts called myofibroblasts multiply in greater numbers than normal. These cells contract and pull, increasing tension in the healing wound, which further stimulates collagen production in a self-perpetuating cycle.^[7]

Various growth factors and cytokines—chemical messengers that control cell behavior—become dysregulated in hypertrophic scarring. One particularly important growth factor, transforming growth factor-beta (TGF-β), appears in abnormally high levels in hypertrophic scars. This growth factor powerfully stimulates collagen production and is thought to play a key role in driving the excessive tissue formation characteristic of these scars.^[4]

Mechanical forces also matter. When skin experiences constant tension or repeated movement during healing, mechanical stress signals cells to produce more collagen. This explains why hypertrophic scars form more readily in high-tension areas or across joints. The pulling and stretching of healing tissue essentially tells the body that more reinforcement is needed, triggering the overproduction of scar tissue.^[4]

Inflammation that persists longer than normal contributes to the problem. Prolonged presence of inflammatory cells in the wound keeps sending signals that stimulate tissue production. When inflammation is resolved quickly, healing proceeds normally. But extended inflammation, whether due to infection, repeated injury, or other factors, increases the risk of hypertrophic scar formation.^[3]