By Mace Laith
Two people can have the same incision, surgeon, and aftercare but end up with very different scars. Scar genetics explains part of that gap, along with skin tension at the site, age and hormonal status, and how the wound was closed. Understanding your own risk profile before surgery is what makes prevention possible, because scars are far easier to influence early.
Nearly every patient asks some version of the same question before surgery: what will the scar look like? It is a fair question, and the honest answer starts with scar genetics, because how you heal is partly written into your biology before anyone picks up a scalpel. Some people form a fine white line that fades into the skin. Others form a raised, firm, persistent scar from an injury no worse than a vaccination. That difference is not carelessness or bad luck, and it is not usually about the technique alone. At The One Plastic Surgery Center in Newport Beach, board-certified plastic surgeon Dr. Siamak Agha reviews scar history during consultation for exactly this reason: knowing who is likely to scar heavily changes where incisions go, how they are closed, and what aftercare gets planned from day one. Here is what the research actually shows.
How a Scar Forms in the First Place
A scar is the body’s repair patch, not a failure. Wound healing moves through overlapping phases: an inflammatory phase lasting several days, a proliferative phase where fibroblasts lay down collagen and new blood vessels form, and a remodeling phase that reorganizes that collagen over months.
StatPearls describes remodeling as beginning around week three and continuing for up to a year, with tensile strength peaking at roughly 80 percent of uninjured skin. It never reaches 100 percent.
That long remodeling window is why a scar seen at six weeks tells you very little. Redness, firmness, and thickness commonly peak in the first few months and then soften. It is also why the most useful interventions start early, while collagen is still being reorganized rather than settled.
Hypertrophic Scars and Keloids Are Not the Same Thing
Both are raised scars, but they behave differently. A hypertrophic scar stays within the boundaries of the original wound and often flattens partially over time. A keloid grows beyond the original wound edges into surrounding normal skin, does not regress on its own, and tends to return after removal.
The distinction matters because the treatment plans diverge. Hypertrophic scars often respond to pressure, silicone, and time. Keloids usually require combination therapy and close follow-up.
The American Academy of Dermatology reports that between 50 and 80 percent of keloids shrink after corticosteroid injection, though many regrow within five years, and that nearly all keloids return when they are surgically removed without additional treatment. That single fact reshapes how surgery on a keloid-prone patient is planned.
“A hypertrophic scar stays inside the wound’s borders. A keloid grows past them and rarely regresses alone.”
Scar Genetics: What Family History and Ancestry Predict
Scar genetics is not one gene. Keloid tendency clusters in families and twins, and the Textbook on Scar Management chapter on keloid genetics describes an autosomal dominant pattern with variable expression, meaning the trait can run through a family while showing up more strongly in some members than others.
Ancestry is part of the picture too. That same chapter notes reported keloid prevalence as high as roughly 16 percent in some African populations, with higher rates also described in people of Asian descent. This is a population-level pattern, not a prediction about any individual.
Newer work adds precision. A 2025 multi-ancestry genome-wide meta-analysis in Nature Communications drawing on nearly 7,900 keloid cases identified 26 associated genetic loci and estimated heritability at roughly 6 percent in European ancestry groups, 19 percent in East Asian ancestry groups, and 34 percent in African ancestry groups. Implicated genes clustered around integrin signaling, fibrosis pathways, and sex hormone signaling.
The practical translation is simple. If a parent or sibling forms thick scars, or if you have formed one yourself from a piercing, acne lesion, or minor cut, that history belongs in your consultation.
Beyond Scar Genetics: Tension, Body Site, Age, and Hormones
Genes set a baseline. Mechanics adjust it. Skin under constant pull heals worse, which is why the same person can have an invisible scar on one part of the body and a thick one somewhere else.
A review in Frontiers in Immunology on mechanotransduction in scarring notes that joints, the lower abdomen, and the sternum are among the sites most prone to hypertrophic scarring, and that incisions running perpendicular to natural skin tension lines scar more than those running parallel to them. Mechanical stress activates fibroblast signaling that drives collagen deposition.
Age and hormonal status matter as well. Research summarized in Frontiers in Physiology describes estrogen as a major regulator of skin repair, with collagen dropping sharply in the years after menopause and healing slowing accordingly. Interestingly, that same literature notes that estrogen-deficient skin can deposit less matrix, which sometimes produces a thinner scar even though healing takes longer.
- Wound tension, not just technique, drives how thick a scar becomes
- The chest, shoulders, upper back, and lower abdomen are higher-tension zones
- Younger patients often heal faster but can scar more actively
- Smoking, poorly controlled diabetes, and some medications affect healing
Scar Treatments the Evidence Actually Supports
Scar care is most effective when it starts early and continues consistently. The AAD’s scar treatment overview describes silicone sheets and gels, pressure therapy, corticosteroid injections, laser and light treatment, and surgical revision as the mainstays, with combination approaches generally outperforming any single option.
Silicone is the most accessible first step. Sheets tend to outperform ointments, and both require daily use over months rather than weeks. Pressure garments, worn many hours a day, are standard after larger wounds and burns.
Corticosteroid injection remains the workhorse for raised scars, often reducing size by half or more across repeated sessions. For flat but discolored or textured scars, resurfacing enters the conversation.
A recent meta-analysis of eight randomized trials comparing fractional CO₂ laser with radiofrequency microneedling for post-acne scarring found the laser produced greater scar improvement, while radiofrequency microneedling had a more favorable safety profile, with less pain, shorter redness, and a lower risk of post-inflammatory hyperpigmentation. That tradeoff is the reason both technologies exist side by side. The practice offers CO₂ laser skin resurfacing as well as RF microneedling, and which one suits a given patient depends heavily on skin tone, scar type, and tolerance for downtime.
Sun protection is the least glamorous item on the list and one of the most important. The AAD advises broad-spectrum SPF 30 or higher over healing scars and avoiding tanning beds, since ultraviolet exposure can darken a scar semi-permanently during its first year.
“Scar care works best when it starts early, continues for months, and combines more than one method.”
How Scar Genetics Shapes Surgical Planning
A surgeon cannot change your genes, but knowing them changes decisions. During consultation, a thorough assessment covers personal and family scarring history, prior surgical or piercing scars, skin tone and type, the planned incision site, medications, nicotine use, and conditions that affect healing.
That information drives concrete choices. Incisions get placed in natural creases or along tension lines where anatomy allows. Deep closure is designed to carry the load so the skin edges sit together without pull. Follow-up scar care, including silicone, taping, and early injection when appropriate, gets scheduled rather than improvised.
For patients already living with a scar that bothers them, scar revision is its discipline. It generally waits until the scar has matured, and it aims to trade a wide or poorly placed scar for a better-positioned, lower-tension one, often combined with resurfacing or injections afterward. The practice’s revision plastic surgery page outlines how those cases are approached, and incision planning is a standing topic in procedures like a tummy tuck, where the scar’s position is part of the surgical design.
No surgeon can promise a particular scar. What a careful plan can do is remove the avoidable variables and address the rest early.
Key Takeaways
- Scar genetics is polygenic, runs in families, and varies by ancestry, with heritability estimates differing substantially between population groups.
- Hypertrophic scars stay within the wound borders while keloids extend beyond them and commonly return after removal alone.
- Skin tension, body site, age, and hormonal status modify genetic risk in both directions.
- Silicone, pressure, corticosteroid injection, laser or RF microneedling, and sun protection have the strongest supporting evidence, especially in combination.
- Sharing your scarring history before surgery lets your surgeon adjust incision placement, closure, and aftercare from the start.
Every patient is different. Results, risks, and candidacy vary from person to person, and only an in-person consultation with a qualified surgeon can determine whether a specific procedure or scar treatment is appropriate for you.
Planning Around the Way You Heal
Scars are not entirely within anyone’s control, and any practice that suggests otherwise is overselling. What is within reach is a plan built around how your skin actually behaves: incisions placed thoughtfully, closure that takes tension off the skin, early and consistent scar care, and treatment options matched to your skin tone rather than applied generically. If you have scarred yourself heavily in the past, that is information worth bringing to a consultation rather than worrying about it alone.
Ready to find out which scar prevention or scar treatment approach is right for you? Schedule a consultation with board-certified plastic surgeon Dr. Siamak Agha at The One Plastic Surgery Center in Newport Beach to discuss your goals and options.
Frequently Asked Questions
Can genetics really determine how I scar?
Genetics influences scarring substantially but does not decide it alone. A 2025 multi-ancestry study identified 26 genetic loci linked to keloid risk and found heritability estimates that varied widely between ancestry groups. Skin tension at the wound site, age, hormonal status, and how the wound is closed all interact with that inherited baseline.
What is the difference between a hypertrophic scar and a keloid?
A hypertrophic scar remains within the borders of the original wound and often softens and flattens over months. A keloid extends beyond the original wound into surrounding skin, does not regress on its own, and frequently returns after surgical removal unless combined with other treatments. A clinician can usually tell them apart on examination.
When should I start treating a surgical scar?
Once your surgeon confirms the incision has fully closed, which is commonly a few weeks after surgery. Silicone sheets or gel, taping to reduce tension, and daily sun protection are typical first steps. Scar remodeling continues for up to a year, so early and consistent care has more influence than treatment started late.
Is CO₂ laser or RF microneedling better for scars?
It depends on the scar and the skin. A meta-analysis of randomized trials found fractional CO₂ laser produced greater improvement in acne scarring, while radiofrequency microneedling caused less pain, shorter redness, and a lower risk of post-inflammatory hyperpigmentation. Skin tone, scar type, and acceptable downtime guide the choice, which is decided at consultation.
Does sun exposure really affect scars?
Yes. The American Academy of Dermatology advises applying broad-spectrum SPF 30 or higher over healing scars and avoiding tanning beds. Ultraviolet exposure can darken an immature scar, and that discoloration may persist long after the scar itself has softened. Protection matters most during the first year.
