Scar Tissue Formation in Dogs: How Canine Skin Heals Differently

Based on peer reviewed veterinary research · For educational purposes only · Updated October 2026 · 9 min read

What Is Scar Tissue in Dogs?

Scar tissue in dogs is the fibrous connective tissue, built mainly from type I collagen, that permanently replaces normal skin after an injury damages the dermis (the deep, structural layer of skin). Superficial scrapes that only affect the epidermis (the thin outer layer) regenerate without scarring. Once a wound reaches the dermis, the body can no longer rebuild the original architecture and instead lays down a patch.

That patch works, but it is a compromise. Normal dermis contains collagen arranged in a flexible, basket-weave pattern, along with hair follicles, sebaceous glands, sweat glands, nerves, and a fine network of blood vessels. Scar tissue contains densely packed collagen bundles aligned in parallel, with few or none of those appendages. The result is skin that is stiffer, paler, and often hairless.

Strength is the other key difference. In classic wound-strength research, healed skin regained only about 20% of its original tensile strength at 3 weeks and plateaued at roughly 70 to 80% after months of remodeling (Levenson et al., 1965). That ceiling applies to dogs as well. A scar is permanently weaker than the skin it replaced, which matters for dogs with repeated injuries to the same site.

How Does Canine Skin Heal Differently From Human and Cat Skin?

Canine skin heals through the same four overlapping phases as other mammals: hemostasis, inflammation, proliferation, and remodeling, covered in detail in The Four Stages of Wound Healing in Dogs. What differs is how dogs weight each phase, and that shapes the final scar.

Contraction dominates. Most dogs have loose, highly mobile skin over the trunk and neck. During second-intention healing (an open wound left to close on its own), myofibroblasts (specialized contractile cells) pull the wound edges toward the center. On the trunk, contraction can close the large majority of a wound's surface area, leaving a scar much smaller than the original defect. On the lower limbs, where skin is tight, contraction is limited and scars stay larger.

Dogs outpace cats. A controlled comparison found that dogs formed granulation tissue sooner, contracted wounds faster, and had open wounds close more quickly than cats. Sutured wounds in dogs also had roughly twice the breaking strength of those in cats at day 7 (Bohling et al., 2004). The difference traces partly to a richer blood supply from the subcutaneous tissue in dogs (Bohling et al., 2006).

Dogs rarely form keloids. In people, hypertrophic scars and keloids (raised scars that extend beyond the original wound) are common after burns and surgery. Dogs can develop exuberant granulation tissue during healing, discussed in Granulation Tissue in Dog Wounds, but true keloid-type scarring is uncommon. A scar that keeps growing is therefore more likely to be something other than a scar.

What Does a Normal Scar Look Like Over Time?

Scars change appearance for months, and knowing the normal timeline prevents unnecessary worry and helps owners recognize when something is off.

Weeks 1 to 3: The healed line is pink to red, slightly raised, and may feel firm. Collagen at this stage is mostly type III, a weaker, disorganized form laid down quickly.

Weeks 3 to 12: Remodeling begins. Type III collagen is steadily replaced by stronger type I collagen, fibers realign along lines of tension, and excess blood vessels regress. The scar flattens and fades from red toward pink or pale gray.

Months 3 to 12 and beyond: The mature scar is flat, pale, and often hairless. In dark-skinned dogs it may be hypopigmented (lighter), or hyperpigmented (darker) if chronic inflammation persisted. Where some follicles survived at the wound edge, hair may regrow white, a change called leukotrichia.

How Do Veterinarians Evaluate a Scar or Healing Wound?

Most scars need no testing at all. A veterinarian examines the site visually, palpates it for firmness, heat, and pain, and compares it with the surgical or injury history. The goal is to confirm that what looks like a scar actually is one.

Further workup is warranted when a scar behaves abnormally. Common diagnostics include:

Skin cytology: tape or impression samples examined under the microscope for bacteria (usually Staphylococcus pseudintermedius) or Malassezia yeast, which can colonize the altered surface of scarred skin and surrounding folds.

Fine needle aspirate or biopsy: used when a scar thickens, grows, or develops a lump. Some tumors, including fibrosarcoma and squamous cell carcinoma, can arise at sites of chronic injury, and a biopsy is the only way to rule them out.

Culture: for draining tracts or recurrent infection at the site, which can indicate a retained foreign body or suture reaction.

If you are unsure whether a change around an old scar is normal, the Dog Skin Condition Checker can help you organize what you are seeing before your appointment.

Can You Reduce Scarring in Dogs?

No topical product erases a scar, and claims to the contrary are not supported by veterinary evidence. What owners and veterinarians can do is give the wound the best possible conditions to heal cleanly, which is the single biggest factor in how the final scar looks.

Close wounds early when possible. Primary closure by a veterinarian within the first hours after injury produces a thin, linear scar. Wounds left open heal by contraction and epithelialization and leave a wider, hairless area.

Prevent licking and chewing. Self-trauma is the most common reason a clean wound turns into a thick, irregular scar. It is also the mechanism behind chronic lick lesions, described in Acral Lick Dermatitis in Dogs. Use an Elizabethan collar or recovery suit as directed.

Control infection. Infection prolongs the inflammatory phase, delays collagen maturation, and increases the amount of scar tissue laid down. Follow your veterinarian's incision care plan, outlined in Post-Surgery Wound Care for Dogs.

Manage the skin around mature scars. Once a scar has fully closed, the surrounding skin can still develop problems. Scars that create folds, or sit in warm, moist regions like the groin, armpits, or lip margins, can trap sebum and moisture, giving Malassezia yeast room to overgrow. After your veterinarian confirms the skin is intact and yeast is involved, a medicated bath may be part of the plan. Yeast Dermatitis Shampoo contains ketoconazole, an azole antifungal that blocks ergosterol synthesis in the yeast cell membrane and reduces Malassezia populations on the skin surface. It is an FDA-registered OTC veterinary drug listed on DailyMed, not a cosmetic shampoo. It does not change the scar itself, and it should never be used on open or unhealed wounds. For more on recognizing yeast involvement, see Yeast Infections in Dogs.

Long-Term Care for Dogs With Scars

A mature scar is permanent, low-maintenance tissue, but it has a few lifelong quirks worth planning for.

Sun protection: Hairless, depigmented scars have no coat or pigment to block ultraviolet light. Dogs that sunbathe or have scars on the nose, ears, or belly are at risk of sunburn, and chronic solar damage is linked to squamous cell carcinoma. Limit midday sun exposure and ask your veterinarian about pet-safe sun protection.

Reinjury: Because scar tissue tops out at about 70 to 80% of normal strength, scars over bony points, paw pads, and working-dog pressure areas tear more easily. Padding, boots, and properly fitted harnesses reduce stress on these sites.

Dryness and cracking: With few sebaceous glands, scars can become dry or scaly. Gentle, fragrance-free bathing and avoiding harsh degreasing products helps.

Monitor for change: Check scars during routine grooming. Any scar that grows, ulcerates, bleeds, or develops a lump after it has matured is not normal and should be examined, since tumors and chronic infections can mimic or arise within scar tissue.

Frequently Asked Questions

Will my dog's hair grow back over a scar?

Usually not. Full-thickness wounds destroy hair follicles, so mature scars are typically hairless. Hair at the edges may regrow white (leukotrichia) if some follicles survived.

How long does it take for a dog's scar to fully heal?

The surface closes within 2 to 3 weeks for most sutured wounds, but remodeling continues for 12 months or longer. The scar reaches only about 70 to 80% of normal skin strength.

Do dogs get keloid scars?

True keloids are rare in dogs. Dogs more often develop exuberant granulation tissue during healing, especially on the lower limbs. A scar that keeps growing should be evaluated for infection or a tumor.

Can I put scar cream on my dog?

There is no veterinary evidence that topical scar creams meaningfully change canine scars, and dogs often lick them off. Ask your veterinarian before applying any product, especially to a wound that has not fully closed.

Sources

1. Bohling MW, Henderson RA, Swaim SF, Kincaid SA, Wright JC. Cutaneous wound healing in the cat: a macroscopic description and comparison with cutaneous wound healing in the dog. Veterinary Surgery. 2004;33(6):579-587.
2. Bohling MW, Henderson RA, Swaim SF, et al. Comparison of the role of the subcutaneous tissues in cutaneous wound healing in the dog and cat. Veterinary Surgery. 2006;35(1):3-14.
3. Hosgood G. Stages of wound healing and their clinical relevance. Veterinary Clinics of North America: Small Animal Practice. 2006;36(4):667-685.
4. Levenson SM, Geever EF, Crowley LV, et al. The healing of rat skin wounds. Annals of Surgery. 1965;161(2):293-308.
5. Balsa IM, Culp WTN. Wound care. Veterinary Clinics of North America: Small Animal Practice. 2015;45(5):1049-1065.
6. Miller WH, Griffin CE, Campbell KL. Muller and Kirk's Small Animal Dermatology. 7th ed. St. Louis: Elsevier; 2013.

Related Reading

• The Four Stages of Wound Healing in Dogs: What Happens Under the Skin
• Granulation Tissue in Dog Wounds: Healthy Healing vs Proud Flesh
• Why Senior Dogs Heal Slower: Age-Related Wound Recovery Explained

E. Maddens

Founder of Vetified. Develops topical antifungal and antimicrobial formulations for companion animals. Vetified products are listed on DailyMed and manufactured through FDA-registered facilities in the United States.

Research basis: All Vetified content references peer reviewed research published in journals including Veterinary Dermatology, JAVMA, and Journal of Small Animal Practice.