Hoof Abscesses
Hoof abscesses are one of the most painful conditions your horse could suffer from, and unfortunately they are complex to treat and occur all too often. In normal conditions, the horse’s hoof is well protected with a hard outer wall and a softer, but very resilient sole. Even the more sensitive frog and heel are remarkably tough and resistant to injury. However, it’s that very resilience that makes hoof abscesses such a challenge, and what makes them so painful.

Abscesses happen when a bacterial infection makes its way inside the hoof, and becomes trapped, so that inflammation and infected material cannot escape. The resultant heat and pressure that build up inside the hoof can cause the horse severe distress very quickly, and can even lead to permanent injury, or even death. Whenever you suspect a hoof abscess, you need to contact a vet immediately, and work with your vet and your farrier to help your horse recover. Even a few hours delay can make the difference between a full recovery and a much worse outcome.

How do abscesses happen?
For the infection to get inside the hoof, often there is some sort of puncture injury or other entry point. The horse may have stepped on a nail (that’s why it's essential to retrieve lost horseshoes from your paddocks!), glass, or even a sharp rock. In some cases, the item may even lodge itself in the hoof. A small stone that gets trapped in the white line area between the wall and the sole can work its way into the hoof, carrying harmful bacteria with it. In other cases, persistent or aggressive infections like thrush, if left untreated, can find their way into the hoof causing an abscess. Horses with poor hoof care, such as those allowed to stand in wet or dirty conditions for long periods, those with very dry feet allowed to crack or chip, or horses ridden on hard ground without shoes who develop a separation of the hoof and the wall, can also have weak spots on the sole or wall that allow bacteria to enter the hoof. Occasionally a previously shod horse that is now going barefoot can be prone to abscesses, as old nail holes and a sensitive sole can allow infection in.

Once the bacteria has entered the hoof, the rich supply of oxygenated blood there enables infection to grow rapidly, and horses usually become very lame very quickly. This can make diagnosis difficult, when a horse that was turned out sound in the morning is on three legs by the afternoon. All too often horse owners look for major bone or soft tissue injuries higher up the leg, when all along the problem was in the foot.

Diagnosis
The prompt and correct identification of an abscess is critical to successful treatment. The horse will undoubtedly be lame, sometimes extremely so. There will be heat emanating from the hoof wall. However, the stress caused by the pain of an abscess can increase the horse’s metabolism, and all hooves may be warm as circulation increases, making the abscess harder to identify. Often the horse will hold the affected foot off the ground, or only allow the toe to touch, and in severe cases the horse may be sweating or breathing rapidly. The lower leg, especially the heel bulbs, may be swollen.

Sometimes - but by no means always - inspection of the hoof will reveal the site of a puncture or another injury, alerting you to the likelihood of an abscess. If you can see an object still in the hoof, do not attempt to remove it yourself - your vet will want to see the object, how it entered the hoof and how far it punctured to be able to better determine treatment.

Treatment
Your first course of action is always to call your vet. Even if the horse doesn't appear very lame, or the hoof doesn't feel very warm, you should seek veterinary advice. A mild abscess can quickly become severe. Your vet will inspect the hoof, remove the shoe if your horse is wearing one, and in mild cases or where there is no visible puncture site may use hoof testers to identify the exact location of the infection. In most cases, your vet will clean the hoof, and gently pare away near the site of the infection until the abscess can drain - this may need to be done with a sedative or pain relief. In very mild cases, or where the abscess has entered through the softer tissues or the frog or heel, your vet may try and draw out the abscess by soaking the hoof in warm salt water, or applying an epsom salt-based hoof pack. However, abscesses can be so painful that in most cases your vet will want to relive the pressure immediately by opening up the hoof.

Once drained, your horse will have instant relief from the pain. The vet may pack the sole and wrap the hoof in cotton and a protective layer of duct tape. You will probably need to change this dressing every day, checking to see if the site is continuing to drain or is healing well. Your horse will probably need to be stabled. Your vet may also administer or prescribe antibiotics or pain relief for your horse. Once your horse is recovering, hand walking on soft surfaces will help to keep the circulation moving and aid healing. You can protect the treatment site with an overboot while your horse is in this phase of recovery. As your horse recovers, keep a close eye on his condition - he could worsen quickly. Look for increased or persistent lameness, loss of appetite, or unusual aggression. If the site continues to drain after three days, or if scar tissue or proud flesh start to form, contact your vet for follow up treatment.

Prognosis
With prompt and aggressive care, most horses with mild abscesses can expect to be sound and able to return to work within a week or two. More severe infections requiring deeper or larger sections of the hoof to be removed may need therapeutic care from your farrier, and your horse could be off work for several weeks.

In very severe or untreated cases, serious complications can occur. The abscess may rupture at the coronary band, separating the hoof wall from the structures of the lower leg, which can result in the horse being euthanized. Large infections in the hoof can press against the pedal bone, causing it to rotate and point toward the sole, or even to puncture the sole from within. Again, in these cases, the outlook for the horse is usually very poor. The stress of the pain an abscess can cause, and the horse's limited ability to move, can cause metabolic disorders such as colic and laminitis as serious secondary conditions.

Prevention
As with any ailment, prevention is much better than cure. A good hoof health routine is your first step to preventing abscesses, including picking out and brushing off your horse’s feet at least daily, providing him with a clean dry place to stand, and ensuring that your horse sees a farrier for regular trimming. Maintain your paddocks too, inspecting them regularly for sharp objects and removing rocks, branches, or other objects that could damage the hoof. When riding, be sensitive to your horse’s feet. Don't gallop on rough or rocky ground, and if your riding is likely to be over tough terrain, consider shoes, perhaps with protective pads.