Foot abscesses are a very common ailment for horses and can be a recurring nightmare for some owners.
Also known as pus in the foot, a horse can be mildly lame or not bear weight on the injured leg.
A foot abscess is caused when a sharp object, for example a stone, penetrates the sole of the hoof and bacteria gets in, and the superficial layers close over, and a localised infection develops. The pressure builds in the foot, causing pain as it touches the nerves and causes the lameness. The foot also becomes inflamed, with a bounding pulse and heat in the hoof.
If you suspect an abscess in your horse then either the farrier or vet can test for pressure points in the hoof using hoof testers. When a sensitive area is pinched the horse will flinch, indicating pain. If a horse has shoes they may need to be removed to access the abscess. That area can then be parred out to release the pressure. When the surface of the abscess is pricked pus usually bursts out, causing a lot of excitement amongst the farriers. I remember our farriers arguing over who got to “hunt the pus”.
Once the dead tissue has been removed the foot needs to be poulticed to keep the abscess clean, allow it to drain and heal. Usually a wet poultice is applied for the first few days before a dry poultice to help dry up the foot before the shoe is replaced. The horse needs to be kept on box rest, and the foot kept as dry as possible, so the bed should be meticulously clean. The poultice needs changing at least once a day. If an abscess is difficult to treat and a prolonged wet poultice is required the sole of the hoof can become soft and thus prone to reinfection, so a hoof hardener can be applied with the dry poultice to strengthen the tissues.
Antibiotics are rarely used in treating abscesses but sometimes a painkiller is used for the first couple of days to keep the horse comfortable. Pus in the foot carries a high risk of tetanus, so it is important horses are vaccinated against it.
Horses with flat feet or soft soles can be prone to foot abscesses, or those with poor foot care and living in wet conditions.