A wound is any break in the normal structure of living tissue, such as a cut, scrape, tear or puncture [1]. Skin heals by a series of steps that blend into each other, and more than one can be going on at the same time [1]. To keep things simple, this guide groups them into three broad stages: inflammation, repair and remodeling. Some vet texts split the same process into five steps by naming stopping the bleeding and clearing out debris as separate stages [1].
This guide explains those stages in plain words. Every wound is different, so your vet is the one to judge how your pet’s wound is doing.
Have your vet check any wound that is deep, bleeding, dirty or from a bite.
Stage 1: inflammation (cleaning up)
The first stage starts the moment the skin is injured. Small blood vessels narrow and platelets clump together to slow the bleeding, and this first response lasts only minutes [1].
White blood cells then travel into the wound to keep infection in check [1]. They break down dead tissue, germs and damaged cells and carry them away [1]. Some of these cells, called macrophages, also send out growth signals that tell the body to start building new tissue [1]. This is part of why a fresh wound can look red, puffy and sore for a while [1].
Stage 2: repair (building new tissue)
The repair stage usually gets going a few days after the injury and can carry on for a couple of weeks or more [1]. It overlaps with the cleanup stage rather than starting at one fixed moment [1].
In this stage, repair cells called fibroblasts lay down collagen, a protein that gives the wound strength, and new tiny blood vessels grow into the area [1]. Together they form granulation tissue, the new tissue that fills an open wound [1]. Healthy granulation tissue tends to look bright red, moist and flat [2]. Your vet will look at it closely at each recheck [2].
Skin cells then creep in from the edges of the wound toward the middle to cover it [1]. In a large wound this takes longer, and the skin cells need a good bed of granulation tissue to move across [1]. Vets also aim to keep an open wound neither too wet nor too dry, because the right moisture balance helps granulation tissue form and helps the edges move in [3].
Stage 3: remodeling (getting stronger)
The last stage is remodeling, sometimes called maturation [1]. During it, the early collagen laid down in the repair stage is slowly broken down and replaced by a stronger type, and the new tissue is reorganized [1]. This is what makes the healed area tougher over time [1]. The scar keeps changing during this stage, even after the surface looks closed [3].
When healing slows down
Some things can hold healing back. For these, see slow-healing wounds in dogs and cats. For first steps with small cuts and scrapes, see minor wound care for dogs and cats.
Care
Your vet will advise on care for your pet’s wound. At home, as directed by a vet:
- keep your pet from licking, chewing or scratching the wound;
- do not put anything on the wound unless your vet says so;
- go back for every recheck.
Outlook
The size of a wound, how dirty it is and how it happened all shape how it is treated and how it heals [1]. A large open wound can take months to close fully, and the scar keeps maturing after that [3]. The healed skin may not look exactly like the skin around it.
These are general points about wounds. They cannot predict how one pet will do. Your vet can explain what this means for your pet.
When to see your vet
See your vet if your dog or cat has:
- any bite wound, even if the marks look small, since bites are a leading reason pets end up with open wounds [2];
- a wound that is deep, bleeding or dirty;
- a healing wound that opens up again or gets worse.
The bottom line
Wounds in dogs and cats heal through overlapping steps that can be grouped into three stages: inflammation, repair and remodeling. Only a vet can judge how a wound is healing, and your vet will advise on care.
This article is for general information only and does not replace advice from your veterinarian. If your pet has a wound, see your vet.
Sources
- Santos JKVRS, Costa EDS, Fernandes CCL, et al. Integrative Therapies in Wound Healing in Small Animals: An Approach Beyond Traditional Medicine. Veterinary Sciences (MDPI), 2026. Open access, CC BY 4.0. https://pmc.ncbi.nlm.nih.gov/articles/PMC13211445/
- Jiménez Lázaro M, Sopena Juncosa J, Martins EJC, et al. Effect of fluorescence biomodulation as an adjunct to standard wound management in open wounds in dogs and cats: a prospective, randomised, within-wound controlled clinical trial. Frontiers in Veterinary Science, 2026. Open access, CC BY. https://pmc.ncbi.nlm.nih.gov/articles/PMC13437437/
- Rodríguez-Aguilar SE, Ocampo-López J, Hernández-Aco RS, et al. Multimodal Management of a Large Postsurgical Wound Secondary to Nodulectomy in a Dog. Case Reports in Veterinary Medicine (Wiley), 2026. Open access, CC BY 4.0. https://pmc.ncbi.nlm.nih.gov/articles/PMC13548134/