Hoof Abscesses

A hoof abscess is a bacterial infection within the sensitive structures of the equine foot. Pus is produced due to the horse’s inflammatory response and, as expansion is not possible within the hoof capsule, the pressure can be extremely painful. The condition is more common in the winter months due to the muddy conditions.

Signs of a foot abscess include:
• Sudden onset and severe lameness usually in one limb, often reluctant to bear weight
• Heat in the affected hoof
• Increased digital pulses (assessed by placing the fingers gently over the inner and outer aspects at the back of the fetlock to feel for the pulse to the foot)
• Possibly swelling of the bottom part of the leg
• May have an increased temperature (normal range 37-38.5 degrees Celsius)

The build-up of pus will eventually break out of the sole of the foot, the coronary band or the heel bulbs however prompt intervention minimises the pain suffered by the horse during the acute stage of the condition. The shoe is removed, hoof testers are used to establish the location of the abscess and the foot is pared, usually following a tract, to allow drainage of the abscess. Once drainage is established the horse will experience significant relief however some residual lameness is to be expected. Following this a period of poulticing may be required to draw out any remaining purulent material. Often if the abscess is deep seated or still developing it may not be found by paring and as excess paring can be detrimental to the horse, the foot should be poulticed to encourage abscess maturation and attempt to ‘draw out’ the abscess. Commercial poulticing material is available from us or most feed shops. The poultice should be trimmed to size and soaked in warm water before applying to the foot over the affected area and fixing in place with bandage material or a purpose bought boot. This poultice should be changed twice daily and the amount of discharge monitored. Some deep seated abscesses can take a significant period of time to develop and rupture, however if you feel your horse has developed an abscess that has taken a prolonged period of time to rupture it is important to seek veterinary advice as potential complications include infection of the deeper structures of the foot such as the pedal bone, requiring far more involved surgery to correct.Treatment of an uncomplicated foot abscess is a procedure that can be performed by your veterinarian or farrier however we stress that if there is any question as to what is causing the pain it is important to consult your veterinarian promptly.

Other conditions that can present in a non-weight bearing lameness include fractures and septic joints, both of which are important to identify quickly!
It is important to monitor your horses feet and pick them out daily in order to minimise the risk of abscess formation and to identify them early if they do occur.

Pus In The Foot

Pus in the foot is a very common cause of sudden, often severe, single limb lameness in the horse. Beneath the insensitive sole there are laminae which are densely supplied with nerves. Abscess formation results in pressure between the sensitive laminae and the rigid dorsal hoof wall and hence pain. It can be compared to infection beneath the finger or toenail. Infection can be introduced; through a puncture in the sole of the foot, nail prick at shoeing, through a crack in the dorsal hoof wall or via the white line.

The affected horse is often extremely lame and may even refuse to weight bear on the affected limb. The foot is often hot and will have a bounding digital pulse. When hoof testers are carefully applied to the sole of the foot there will be a pain response in the region of the abscess. The vet or farrier will remove the horse’s shoe and pare the foot to look for the track of the abscess. If this is found the track can be followed to release the pus and allow it to drain, causing reduction in local pressure and hence pain. A poultice will be applied and changed twice daily and the horse treated with non-steroidal anti-inflammatory drugs and box rest. Tetanus vaccination status should be checked and tetanus antitoxin given if the horse is un-vaccinated or if vaccination status cannot be verified. Antibiotics are rarely given as they may mask an abscess, which will return once the antibiotics are withdrawn. If the pus cannot be located then a poultice will be applied, in order to ripen the abscess and the horse re-examined in 48 hours. If there is no improvement and the horse remains lame then radiographs may be taken to identify the pocket of gas and ensure that a pedal fracture is not present. Sometimes the abscess may track further along the sole or even break out at the coronary band. Once the abscess has finished draining the sole of the foot needs to be kept clean and dry to prevent reinfection.

Prevention of foot abscesses involves; good farriery and trimming, regular picking out of the feet, avoidance of waterlogging of the feet and good diet to maintain strong horn and white lines. Any solar penetrations should be cleaned and poulticed without delay and advice sort from your veterinary surgeon. Tetanus vaccination is important as potentially fatal infection can gain access through hoof injuries.