Often called a stone bruise, a foot abscess is in fact an infection within the hoof that develops into an abscess and as the pus builds up, causes a lot of pain due to the pressure from the containment within the hoof. The infection stems from what can be just a tiny crack and the bacteria get in to the inner area of the hoof. After about 10-14 days the horse will become very lame and that can be alarming to the owner as they can be very reluctant to move or put any weight on the foot.
Diagnosis is form testing the walls and sole of the foot for a reaction to pressure and this may pinpoint where the abscess is located, a bounding digital pulse may be present, and the presence of heat in the wall or sole or even around the coronet. In more severe cases that have not been picked up early there may be swelling up the leg.
The remedy is to relieve the pressure and the horse will immediately show an improvement. This can be achieved by soaking the foot in a bucket (or poultice boot) with warm water and Epsom salts for 5 – 10 minutes. Then applying a poultice and protecting that with a bandage, and if the horse is in a paddock a rubber boot or some device to keep the foot dry and clean. A useful device is an inner tube which can be slid over the foot and doubled up so that it is up above the fetlock. Soft bandage the leg above the fetlock then use a waterproof tape like duct tape to wrap the ends of the tube onto the bandage. Continue poulticing until the pad shows no discharge when removed.
If dealt with quickly and early enough this can often draw out the pus without the need to cut into the foot. A veterinarian or a farrier can create an incision in the sole and obtain drainage. Then poulticing will cleanse the foot and should be continued for at least 2-3 days. In cutting into a foot care must be given not to disrupt the integrity of the foot and too much paring or cutting may create further problems requiring a much longer recovery.
Once the abscess has been drawn it is important to keep the sole clean until it heals, the use of Stockholm tar is helpful here and maybe if a hole has been cut a small wad of cotton wool soaked in the tar will reduce the risk of another infection. The tar will help harden up the sole which may have become soft from the dampness of the poultice.
Keeping the feet in good condition is a good prevention, weak unhealthy feet with thin soles are going to be more vulnerable. The Farrier can assist horses with low flat soles. Using a supplement to assist quality hoof growth will be a useful prophylactic but needs to be given long term as hooves take months to growth down quality wall from the coronet.