An abscess within the hoof is a common cause of sudden, severe, non-weight-bearing lameness in horses. Pain is the one unmistakable symptom of a hoof abscess. Horses will completely refuse to bear weight on the afflicted foot. Owners unfamiliar with this cause of lameness often feel that their horse must have a broken bone.
Pain may be so severe and unrelenting that veterinary involvement and imaging may be necessary to rule out laminitis, a severe bruise, or a fractured coffin bone. More commonly though, a diagnosis of hoof abscess is made by localizing the source of pain and heat to the hoof and coronary band. Other clinical signs include a bounding digital pulse with swelling and congestion in the pastern/fetlock region.
Hoof abscesses occur for a number of reasons. They can occur when foreign material or bacteria gain entry into the hoof capsule via an entrance point. Such entry can occur through defects along the white line or through hoof wall cracks/ fissures. Hoof abscesses are also a possible sequel when the horse’s sole is punctured or as a result of a misplaced farrier’s nail.
More often an abscess is the result of damage to the corium or nail bed within the hoof capsule. Such damage could be caused by bruising/trauma to the sensitive structures within the hoof, a recent episode of laminitis, lack of circulation, or as a result of incorrect hoof form or shoeing. When the underlying corium is damaged or devitalized, the stage is set for the abscess process. Enzymes released in the abscessing process lead to tissue necrosis and the development and accumulation of a grey/black exudate. Increasing pressure within the unforgiving structures of the hoof capsule leads to pronounced lameness. The acidic nature of the exudate dissects along soft tissue planes, finally exiting out the coronary band, heel bulbs, or point of the frog, wherever it finds the easiest path. Once drainage is established the horse’s lameness generally subsides.
The most important aspect of treating a hoof abscess is to establish drainage. The size of the opening needs to be sufficient to allow drainage, yet not so extensive as to create unnecessary damage to the hoof structures. If pain can be localized in the hoof and a small black line or tract identified, a small, well-placed hole may be made with the use of a hoof knife or loop knife. Drainage of a black or brown exudate often provides immediate relief for the horse.
When the specific location of the abscess cannot be identified or is too deep in the hoof, no cutting or holes will be made. Abscesses can and do find their own exit. Poulticing is a practice which expedites the body’s own abscessing process, minimizing the amount of discomfort for the horse.
Two equally effective options are available to the owner to poultice the hoof. One option is to soak the horse’s hoof a number of times daily in Epsom salts and very warm water. Another option is to fashion a “poultice boot” using Animalintex or any number of home remedies within a special treatment boot. When poulticing the hoof it is important to incorporate the coronary band in the soak or the boot. Poultices are an osmotic which draw the abscess bringing resolve relatively quickly.