Everyone knows that when you’re injured your body creates scar tissue. And while scar tissue is far from perfect — it is never as strong as the original tissue except in the case of bone, and it is generally far less elastic and can restrict mobility, as some examples — scar tissue is usually a good thing. It fills in the holes where our normal tissue is missing. With animals, this is no different.
Wounds on a dog, cat, horse, cow, and even snake heal in the same manner as human wound healing. But, as with many things in veterinary medicine, there are important species differences.
Let’s talk about a common problem in horse wound healing called "proud flesh," also known as exuberant granulation tissue.
Occasionally, when a horse gets a leg wound, the healing tissue produces excessive scar (granulation) tissue, which can actually inhibit further healing. This is called proud flesh, an odd name but totally fitting for the circumstances — it’s like the tissue is too proud to back down.
Proud flesh is easy to spot — a large mass of pink tissue pouring out of where the wound once was. Sometimes it can almost look like a growth on the leg. Proud flesh is pretty much a problem exclusive to the lower limbs of horses and is likely due to a combination of factors, such as excessive movement at the wound site, bacterial contamination of the wound, and the minimal blood supply that is characteristic of a horse’s lower limbs, which are made up of bone, ligament, and tendon, not blood vessel-rich muscle.
The primary problem with proud flesh is that new skin cannot grow over it — the final step in wound healing called epithelialization. Therefore, it remains a large mass of unprotected fresh tissue susceptible to infection and further trauma. Because of this, proud flesh needs to be removed.
On wounds with a small amount of proud flesh just protruding over the edges, applying a steroid ointment under a bandage wrap can prevent further granulation tissue from growing and encourage skin to cover the wound. Anything larger, however, needs to be surgically removed. Luckily, proud flesh has no nerve fibers. Unluckily, it has lots of blood vessels. So, if you surgically remove it, the horse won’t feel it, but will bleed a lot.
Therefore, depending on how much needs to be removed, you can either do this at the barn with the horse standing or at a clinic with the horse sedated. One thing I’ve learned when dealing with proud flesh: always warn the owners that it will bleed! After removal, a bandage will need to be applied to the leg to stop bleeding and prevent further development of proud flesh.
Preventing proud flesh is obviously easier that dealing with it once it’s present. If a horse has a lower leg wound that is too big to be stitched closed, it is imperative to properly bandage the wound as it heals. Bandaging goes a long way in preventing proud flesh, but it’s not fool proof. Sometimes even the best bandaged wounds will grow too much scar tissue. If this happens, all is not lost. Prompt attention before the scar tissue becomes too proud is the best way to go.
Dr. Anna O'Brien