Tuesdays with Tony

Did you know that horses only sleep about 3 hours a day? I’m pretty sure they spend the other 21 hours thinking of ways to hurt themselves. Cats, being far superior to horses, sleep 21 hours a day and think about eating the other 3 hours, which is a much better use of time, in my [not humble] opinion. But I digress.

If you’re caring for a horse, you’ll certainly have to deal with a wound at some point. While many wounds can be straightforward to manage, injuries to the lower limbs are especially prone to complications. One way the healing process might go awry is by the development of “Proud Flesh” (more officially called exuberant granulation tissue) – a pink, bumpy tissue that bulges from the wound. Once proud flesh occurs, it’s difficult for the skin to grow together and cover the wound. What results is a chronic wound that just won’t finish healing. Very frustrating!

What Is It?

To understand what proud flesh is, let’s briefly talk about how normal wound healing works. There are four steps: In simple terms, they are:
• Clotting
• Inflammation
• Rebuilding of tissue (proliferation)
• Remodeling into mature tissue

As part of the proliferative phase, the wound fills in with granulation tissue to provide a base for the new skin to grow in on. You’ve probably seen granulation before – it’s pink and bumpy and looks a bit like cauliflower or cobblestone. It’s a normal part of wound repair and is eventually replaced by mature tissue when the wound is healed. Once the new skin cells migrate in from the edges and cover the wound, the signal for the body to make granulation tissue is switched off. When all goes right, these steps proceed in an organized way.

Sometimes this process doesn’t work like it’s supposed to, leading to abnormal wound healing and the production of way more granulation tissue than needed. That’s when we call it “exuberant” or use the term proud flesh. For a variety of reasons, the proliferative phase of wound healing isn’t properly limited, and a bulging mass of granulation tissue grows out of the wound, preventing the skin edges from being able to come together.

Horses, being the problematic critters they are, are more prone to proud flesh than other species. Several factors promote excessive granulation tissue – contamination or infection of the wound, motion in the tissues, poor blood supply, a foreign body or necrotic tissue, and chemicals applied to the wound. These things can slow or halt the normal progression of wound healing and the body gets stuck in the “must produce granulation tissue!” stage.

Most of the time, proud flesh is a problem that occurs on the lower limbs. Being near the ground, the lower limbs are particularly prone to contamination with dirt or manure. The skin is naturally under more tension than higher up on the body and a lot of motion occurs over the joints as the horse moves. This causes cracks in the healing tissue, so inflammation persists, and more granulation tissue forms. When proud flesh occurs in other areas of the body, there is usually a specific reason, such as a foreign body in the wound.

How To Prevent It?

Because persistent inflammation and infection are contributors to proud flesh formation, it’s important to make sure the wound is clean, healthy, and properly managed from the beginning.  Have my doc examine the wound when it first occurs, don’t wait until it looks nasty. She’ll clean the wound appropriately and remove any foreign material, bone fragments, or dead tissue. Depending on the wound, she may recommend trimming damaged tissue or closing it with sutures.

Once the wound is prepared, my doc will recommend the appropriate ointment and bandaging technique for your horse’s specific injury. There are a lot of wound products sold over the counter that actually backfire on well-meaning owners and slow down wound healing, so be careful what you reach for! (Pro Tip – if it’s bright purple or fluorescent yellow, don’t put it on your horse’s wound. And no powders, ever!)

Good products to keep in your first aid kit are triple antibiotic ointment, Silver Sulfadiazine cream and medical grade honey. These dressings are antibacterial but also gentle and keep the wound moist, which is important for healing. Harsh chemicals or repeatedly washing and scrubbing a wound can damage the delicate new skin cells trying to grow and cause proud flesh to form. Don’t kill them with kindness!

Bandaging of a wound is decided on a case-by-case basis. The benefits of bandaging include reducing contamination and limiting movement of the healing tissue. However, some studies have shown that heavy bandaging can encourage proud flesh by limiting oxygen to the wound. The type of bandage can have an effect, so my doc may recommend one kind for the first few days and then switch to a different one as the wound progresses. Depending on the location, she may recommend resting your horse in a stall or small paddock to limit his movement and the stress on the wound edges.

How Do We Treat It?

Sometimes, despite your best efforts, proud flesh happens. Horses do love to make it! My doc will examine the wound for causes of lingering infection or inflammation. She may need to take x-rays or do an ultrasound to look for bone fragments or a foreign body. Antibiotics may be needed to control infection. Because there can be other growths that look similar to proud flesh, such as summer sores, sarcoids, or certain cancers, my doc may recommend a biopsy to be sure it’s definitely just proud flesh.

If the proud flesh is minor, appropriate wound care and topical creams may be sufficient to resolve it. A wound cream with a steroid can help to reduce the inflammatory response and turn off the signal to produce granulation tissue. Steroids aren’t a panacea though and should only be used once my doc has checked out the wound, because if there is infection present, steroids can make it worse.

The most effective treatment for significant proud flesh is to trim excessive tissue surgically. Because the proud flesh is taller than the surrounding skin edges, it forms a mountain that the new skin cells can’t climb over. The goal of surgical debridement is pretty simple – the proud flesh is cut back to just below the level of the surrounding skin edges. If the wound has been present for a while, the skin margins may be unhealthy and require a little trimming as well to create a fresh edge that is ready to heal. Proud flesh bleeds a lot, since it’s full of tiny blood vessels, but since it doesn’t have nerve endings, trimming it isn’t painful for the horse. Usually, the procedure can be done on a standing horse with just a little sedation. General anesthesia is rarely required, and my docs often don’t even need to numb the area unless they need to trim unhealthy skin.

Afterwards, the new skin can continue growing inward from the edges. This process may need to be repeated a few times, depending on the size of the wound. If the wound is so large that the skin can’t easily grow over it, your horse might be a candidate for skin grafts. Small pieces of healthy skin are taken from another area (often the top of his neck under the mane) and plugged into the granulation tissue of the wound. The little islands of skin grow where they are inserted and speed up the rate of healing.

So when your horses gets a wound, work with my doc to treat it correctly from the beginning. Early intervention and good management are always the keys to quick and successful wound treatment. Now that’s something you can be proud of!

Until next week,

~ Tony

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