A relatively frequent call I receive is from a horse owner with a horse that was fine yesterday evening but is toe touching lame this morning. The lameness is often described as seeming to originate from the shoulder or hip depending on whether a front or hind limb is involved. As with most lameness cases without an obvious cause, however, the best place to start is usually the foot.
A sole abscess is usually the result of some penetrating injury to the sole of the foot or the migration of bacteria and debris from some disruption near the white line. Under normal conditions, the sole is relatively hard and not very susceptible to this occurrance but wet conditions favor softening of the sole much like our fingernails soften after a long shower. These do seem to occur in waves on some farms following wet weather. Prevention of sole abscesses is in accordance with prevention of any disease of the foot and is primarily aimed at hygiene and providing a clean, dry environment and appropriate farriery.
The diagnosis is usually uncomplicated. Usually this presents as an acute, severe lameness of a single limb. The hoof wall is often warm compared to unaffected feet and digital pulses are often increased compared to unaffected feet. Hoof testers can be used to confirm the presence of a painful foot and to isolate the tender area. Depending on the horse’s temperament and pain tolerance, regional anesthesia is sometimes employed after applying the hoof testers to make the horse more comfortable and aid in treatment.
The treatment for this problem is all about establishing drainage. The pain from this condition results from pressure so it makes sense that relieving the pressure will relieve the pain. Usually this can be accomplished with a hoof knife or Dremmel tool if a tract can be identified. Foot soaks with betadine solution or Epson salt are frequently used to cleanse the foot or, some believe, to create an osmotic gradient to draw the exudate out of the abscess respectively. Currently, my favorite method after I have established drainage or for those that I cannot find a tract to establish drainage through, is to use an Animalintex poultice and a duct tape boot. This bandage is placed and left on for 24-48 hours. Most of the time the horse becomes sound during that time frame. If not, removing the bandage and re-examining the foot is necessary to rule out anything that might be complicating resolution or make another attempt at establishing drainage. The Animalintex poultice contains an exotic ingredient called tragacanth and boric acid. I will confess that I do not know what effect those ingredients are supposed to have other than softening the foot to facilitate drainage, but this method has proven so effective I have not felt it was necessary to soak a foot for an uncomplicated abscess in a while. Sometimes if there is an open solar defect we have to continue to bandage the foot and treat with topical medications as necessary.
I think it is also a good idea for these horses to receive a tetanus toxoid booster if it has been more than 6 months since their last dose.
Obviously, not every rapid-onset, severe lameness is an abscess, so it is always best to treat the situation with the enthusiasm it deserves and call your veterinarian to take a look. The good news is, if an abscess is diagnosed and an appropriate treatment plan instituted, there is usually an excellent prognosis and most horses will be back to work in short order. If you have a problem with a horse, lameness or otherwise, that you’d like some help with, please feel free to call or e-mail. We would love to help any way we can!