The Stages of Wound Healing in Horses

Fresh and swollen! Courtesy of Lauren B.

There are 4 Stages of Wound Healing in Horses

• Equine wound management begins with noticing the cut, scrape, or open injury, followed by cleaning, possibly wrapping, and maintaining a clean, dry environment to promote a healthy blood supply, alleviate pain, and prevent infections.

Stage 1 of Equine Wounds – Inflammation

• All cuts or injuries, regardless of size, go through this “angry stage.”

• Many things are happening here. There’s a retraction of the skin. The blood flow to the area will also constrict and dilate during this process, reducing the overall blood flow to the area. Vital blood components like fibrin and platelets come to the wound. There will also be an influx of white blood cells that clean out the area and activate the fibrin to start clotting.

• The inflammation during the angry swelling stage causes pain. There will be heat, swelling, pain, and redness. Even if you can’t see or feel those things, it’s happening on some level.

• Many wounds benefit from therapies like medications and ice to help reduce inflammation and pain.

• Horse owners need to avoid rubbing alcohol and hydrogen peroxide during this stage, and all other stages, as these topicals create more damage to healthy tissue.

This article outlines the risks of cleaning wounds with hydrogen peroxide. Use water instead!

Granulation tissue is full of vessels! Courtesy of Mickensey J.

Debridement Happens in Stage 2

• Stage 2 is when your horse takes out the trash. Healing will remove dead tissue and clean out the wound.

• While this is a totally natural process, your horse can get in his own way here. As neutrophils, a type of white blood cell, land in the area, they will eat any bacteria. But they can be overwhelmed and create pus, which ultimately slows healing.

• Another part of this phase is called epithelialization, where new skin cells move to cover the area. Of course, horses are bizarre, and on their bodies, this process moves at about .2 mm a day. On legs, the epithelialization can move less than .1 mm a day. This is one reason why proud flesh develops on lower limb wounds – the skin heals too slowly over the area.

• There may be new blood vessels forming and wound contraction during this stage, too.

Puncture wounds

• In some cases, such as punctures, the wound closure occurs quickly, but the deeper structures continue to heal. This process effectively traps bacteria and white blood cells, creating pockets of infection. In distal limb wounds, this is especially dangerous as there are many delicate structures, such as tendon sheaths, ligaments, and other soft tissues to contend with.

• Some punctures result directly from a sharp object, while others involve a foreign body lodging in the area. Both are bad.

• Management of equine wounds in this stage is critical to reduce the risk of infection.

Stage 3 is Repair

• As healing progresses, the area begins granulation tissue formation.

• This typically occurs 4-5 days after the wound develops. Here, the fibroblast cells are filling the area. They seek each other out as if it’s a giant party. This allows granulation tissue to form, providing a structure for skin cells to migrate over.

• This process may take longer in severe cases versus superficial wounds, and sometimes, the extent of skin stretching can impact healing. Wounds on horses’ joints are constantly being pulled, and the joints may not want to come together fully.

Proud flesh

• Exuberant granulation tissue, known as proud flesh, prevents the skin cells from covering the wound. This excessive granulation tissue bulges out, preventing the skin from closing over it.

• Proud flesh requires veterinary care and can significantly prolong the wound healing process. Surgical removal of excess tissue may be necessary.

Stage 4 of Wound Healing in Horses is Maturation

• Now the injury can finish healing, and perhaps create scar tissue.

• Here, the skin starts to return to normal. This can go on for months and months! Delays to healing include the pus above, too many bandage changes that disrupt the healing process, drying out, and proud flesh. Keep your vet in the loop and keep up with appropriate care.

Almost done. Courtesy of Bree L.

Tidbits About Horse Injuries

• Both the smallest and the most significant wounds will go through the same process.

• Because horses like to throw kinks into our plans, you should always consult your vet about any injury.

• Some cuts require wound lavage and stitches, while others need to remain open and draining, and some may require surgery to promote healing.

• Other treatments include a booster vaccination against tetanus infection, wrapping, skin grafts, topical medications, and stall rest.

• Most horses receive a tetanus toxoid vaccine regularly, but a touch-up may be warranted.

• It can be difficult to cover or wrap anything that’s not a lower leg wound, so ensure your horse’s environment is as clean as possible. Sometimes, a clean cloth or blanket can cover larger body areas. For legs, ensure the bottom of the bandage is low enough to cover the entire region.

• Also, be careful about what type of topical goop or spray you use. It’s not always ideal to dry things out with a colorful spray. Your vet can help you determine the best combination of bandages, wraps, and medications.

• Silver sulfadiazine is excellent for burns and scrapes, and your vet can advise you about specifics.

• Clinical research also suggests that topical corticosteroid creams are helpful.

• There may be oral medications, such as NSAIDs for pain or antibiotics, to boost your horse’s healing.

• Ensure your horse’s first aid kit is stocked with clippers, bandages, and non-stick pads at the bare minimum.

This abstract discusses triamcinolone, a potent topical steroid, and how it helps with injuries.

Monitor Your Horse for Signs of Infection

• The first step to preventing severe infection is to keep injuries clean and dry. Then watch for these signs of infection:
• Fever
• Lethargy
• Heat or swelling around the area
• Decreased appetite
• Oozing or fluid leaking from the area
• Any behaviors that are out of your horse’s regular routine

All of the stages! Courtesy of Tish T.

Wound healing in horses takes time, and there may be setbacks. The most important steps are to consult your vet and closely monitor your horse for signs of infection.