Occasionally, a horse owner encounters a horse or pony with an unusual, firm swelling at the point of the elbow. More than likely this swelling is a shoe boil, also known as a capped elbow or olecranon bursitis — an inflammation of the synovial fluid sacs that support the elbow joint.
Repeated trauma to the bursa causes swelling and other signs of inflammation such as heat and tenderness.
As its name suggests, a shoe boil usually is caused by the heel of a horseshoe consistently rubbing the elbow when a horse is lying down. Repeated exposure to hard surfaces, especially in stalls, and long periods of recumbency also might contribute to the formation of a shoe boil, although by and large heel-to-elbow contact causes the majority of problems.
Lameness does not often occur in cases of shoe boil, but the firm capsule of fluid that builds over the joint eventually can cause it, especially if it compounds an old injury or measures are not taken to reduce heel-to-elbow contact. If the cause of the shoe boil — such as shoes that extend beyond the heel or unyielding stall surfaces — is addressed promptly, minor cases may resolve significantly and perhaps completely. If, however, the bursa becomes severely inflamed or the joint cap is punctured, infection can occur and more serious action may be required.
The most common treatment for shoe boil includes the use of a doughnut-shaped boot that wraps around the pastern and prevents contact of the heel to the upper limb. Combined with conscientious farriery and well-bedded stalls, this protective wear will usually keep further problems from developing. For more serious cases, corticosteroid injections can help reduce swelling, although results generally have been disappointing.
Article courtesy of Kentucky Equine Research. Visit equinews.com/newsletters to subscribe to The Weekly Feed, KER's award-winning equine nutrition newsletter.