Foot Abscess

A foot abscess can be excruciatingly painful for a horse and is probably the commonest cause of a sudden onset severe lameness.

A foot abscess is an infection of the foot that can occur at a variety of locations and for a variety of reasons. They can occur when a bruise (or corn) becomes infected, when a puncture wound occurs, after a nail prick from shoeing, or often for no apparent reason. As an abscess can take several days to develop the inciting cause is often never found.

Once infection has been established an abscess forms. If left untreated there are several possible outcomes. The infection may burst out through a weak area of the sole, often somewhere around the white line, or it may track up through the foot bursting out at the toe or in some cases at the coronary band. Most abscesses never come to this as the degree of lameness seen causes the owner of the horse to seek attention from the vet or farrier.

Diagnosis of a foot abscess can be straight forward or extremely difficult. The application of hoof testers is generally resented by the horse and there is often a bounding digital pulse that can be felt at the level of the fetlock joint. However these signs can also be caused by a variety of other conditions (such as laminitis) making the diagnosis difficult, especially early in the course of the abscess.
This often results in the embarrassing situation where one vet or farrier may look at the foot on one day and find little wrong, only for another vet or farrier to look at the foot a few days later (once the abscess is fully formed) and quickly and easily find the abscess!

If a vet suspects a foot abscess may be present then he will pare away the horn and evaluate any suspicious looking tracts in an attempt to find the abscess, which may be deep within the foot, to establish drainage. Establishing drainage is the key to successful treatment of foot abscesses. Your vet may also have to remove the shoe as many abscesses are found beneath it and would go undetected if the shoe were left on.
Occasionally abscesses may be very deep seated and impossible to find without removing excessive amounts of horn. In these cases your vet may advise poulticing to draw out the abscess and make it easier to locate. In extreme cases an X-ray of the foot may be required to localise the abscess.

Once drainage has been established it is generally advisable to poultice the foot for several days using a wet poultice such as Animalintex. This should ideally be changed three times per day but this can be difficult to achieve and twice daily is satisfactory.

Once the horse is much improved and no further pus is detected when changing the wet poultice, a dry poultice can be used, ideally in conjunction with something to harden the hoof such as Pevidine.

Your vet will advise you on the ideal course of action for your horse depending on the size, depth and location of the abscess.

Once a diagnosis of a foot abscess has been made and treated appropriately, if the horse's lameness has not improved markedly within 2-3 days then the attention of the vet should again be sought as the foot may need further paring. There may also be a second abscess that was previously too small to be detected.

It is essential that if your horse suffers a foot abscess that its tetanus cover is up to date. If not, your vet will need to administer tetanus anti-toxin to proved short term cover, as well as give a tetanus vaccine to re-establish longer term immunity.

In summary foot abscesses are commonplace, can cause horrendous lameness but thankfully in most cases are easily resolved with the horse making a swift and complete recovery.