A Practical Guide to Hoof Abscesses
By Fiona Reed
Hoof abscesses are probably the most common lameness in the horse. Varying in severity and suddenness, they can manifest themselves as mild footieness over a period of time or extreme lameness with a rapid onset. The latter can be very dramatic and cause huge concern and sometimes panic to an owner.
The foot is often hot, and can have a digital pulse. The coronet band can be tender to pressure, as can the bulbs of the heel depending on what part of the foot the infection is centred. There is occasionally but not always filling up the leg. The sole can be sensitive to pressure, specifically when using hoof testers.
More often than not we never know what will have triggered the problem in the first place, but somehow a bit of dirt or foreign body will have entered the foot and an infection will have started. This could be from something as simple as a feint sand crack, a small split in the sole from a sharp stone, an old nail old in the hoof wall from a recent change of shoes, to a more serious puncture wound. Horses with separation from a laminitic attack, or who have seedy toe or very thin soles are more prone, and wet weather can also lead to susceptibility.
Even a small amount of pus within the rigidity of the hoof wall can cause excruciating pain and it is important to get release the pressure as soon as possible by digging out a drainage hole to allow the infection to drain. If you do not have a hoof paring knife or feel confident to do this yourself you should call either your farrier or your vet. My personal first choice, if he can out at short notice, would be your farrier, as he is the specialist in this area and can easily remove any shoe and gently and carefully pare back a hole, tracking any sensitivity until there is sufficient drainage to allow further treatment but not too much that the horse will then be too sensitive on his foot once the abscess is sorted. The horse should show immediate relief once the pressure is released, although will most probably still show signs of lameness.
Once the farrier, or vet, have opened up the sole of the foot, you then need to draw out all the infection, and although gravity will help, it is really not sufficient on its own so we need to apply a poultice. The commonly used nowadays are poultice pads that have active ingredients impregnated and once cut to the appropriate size are wet with hot water and applied onto the sole, covered with padding and kept in place with a cohesive bandage. Tubbing in warm salted water, or flushing salt water into the drainage hole with a syringe is also helpful and can be done daily while changing the poultice dressing. Continue until there is no further infection being drawn out, then change to a dry poultice for a further few days. Other poultices, such as kaolin, bread or bran and Epsom salts are equally as effective, but a bit more labour intensive. While being poultice the horse should be stabled, although if not possible the foot should be heavily taped to try and keep it on and prevent the horse wearing it through.
Antibiotics can be given once the infection is draining but should not be given beforehand as the infection can subside and appear to be cured, only to come back again a few days or even weeks later.
Once the infection is cleared, the sole of the hoof may be very soft and sensitive, and care needs to be taken to prevent re-infection and to slowly harden off the sole. If the hole is fairly small it should dry up and heal over quite quickly and easily on its own, but if a bit bigger you may wish to get your farrier to fit a sole to the shoe. Hydrogen Peroxide and Iodine can help keep the sole and hole both clean and help harden, and the hole can be packed with Stockholm tar for turning out.
Although the vast majority of foot abscesses are easily and rapidly sorted, there will always be a few that take a bit longer or are more challenging. If the infection is higher up in the foot or has started to track upwards it could burst out at the coronet band or bulb of the heel. This is no real problem although you will then be drawing against gravity to clear the infection. On rare occasions the infection can be so extensive that it spreads under the whole sole and is known as an underun sole. This, as can be imagined, can take some time to fully heal and needs careful nursing initially to keep it clean and specialist shoeing until a new sole has grown over. Persistent abscesses can be caused by infection that has developed in several pockets and once you get one cleared up another causes a problem. Any ongoing condition usually has underlying causes such as separation of the laminae and should be investigated by X-Ray.
Foot abscesses can never be totally prevented, but good hoof care, regular visits from the farrier, clean bedding and mud free turnout can all help keep them at bay.