Capped elbow

Capped elbow, sometimes called a shoe boil, is a swelling of the tissue between the skin and the bone at the point of the elbow. It is most often caused by the horse hitting himself with the heel of his shoe when lying down, or lying in a stall with insufficient bedding. It rarely causes lameness, but can develop into a firm, fibrous capsule which may become permanent.

Treatment begins with eliminating the cause. Make sure there is enough bedding in the stall. Try putting a rubber shoe boil roll or donut around your horse’s pastern to prevent him pressing his shoe against his elbow. Cold hosing or icing followed by the application of liniment (topical anti-inflammatory) may be helpful. In serious cases, your veterinarian can treat the capped elbow by injecting it with anti-inflammatory medication or removing it surgically.

Capped hock

This is similar to capped elbow, with the swelling occurring over the point of the hock. It is caused by repeated kicking in the stall or trailer, injury, or by lying on a hard floor without sufficient bedding. Again, begin by eliminating the cause. Put shipping boots on your horse during transport; add bedding to the stall. Turn your horse out regularly so he can wear off some excess energy. Treatment is the same as for capped elbow. A pressure bandage may be helpful in some cases. Capped elbows and capped hocks are considered blemishes (unsightly) rather than unsoundnesses (causes of lameness).

Bone spavin

Bone spavin is a bony enlargement on the lower surface of the hock joint, usually – but not always – on the inside or front. It commonly develops from osteoarthritis caused by repetitive hard work (jumping, racing, polo, reining, etc.) or poor conformation (sickle hocks or cow hocks). It may affect one or both legs. Bone spavin is the most common cause of lameness in the hind legs; it is often seen in older performance horses.

Symptoms often begin with stiffness which improves with exercise. The condition gradually leads to dragging of the toe, uneven gait, poor performance and obvious lameness. Diagnosis is made with flexion tests and x-rays. Treatment includes rest (in the case of serious lameness), changing or reducing the work load, giving anti-inflammatory medication, injections of glucosamine or hyaluronic acid, oral supplements of glucosamine, MSM or chondroitin, and corrective shoeing. With proper maintenance, many horses continue to work for years after being diagnosed with bone spavin.

Note: Not to be confused with bone spavin, bog spavin is a soft, puffy swelling in the hock which does not cause lameness. It is a result of excess synovial fluid and/or thickened synovial tissue and can appear on the front or sides of the joint. It is also caused by working on hard surfaces, conformation problems, or injury.


A splint is a bony outgrowth on the inside – or occasionally the outside – of the cannon bone, most often on the front legs. It is caused by direct trauma (a kick from another horse or being struck by the opposite hind foot), an injury from falling, jumping, racing, etc., poor conformation (base-narrow or toed-out), or faulty movement. Initial painful inflammation will recede, leaving a hard blemish which may or may not be permanent. Rest, cold hosing, stable bandages and anti-inflammatory medication will help until the splint ‘sets’ cold and hard. X-rays can determine if there is a fracture of the splint bone (the rudimentary bone on each side of the cannon bone). If your horse has splints – or if he doesn’t and you want to keep it that way – use polo bandages or splint boots to protect his cannon bones when you ride or turn him out.


If your horse suddenly develops small, round swellings or welts over his neck and shoulders or his entire body, he is probably suffering from urticaria, commonly called hives. This is an allergic reaction to any number of things, including fly spray, detergent, feed, hay, bedding, pollen, insect bites, medication such as butazone, or even cold air. In addition to the welts, there may be itching which the horse will try to relieve by scratching on any available surface. As far as treatment goes, begin by eliminating the source – not always easy to do. Mild cases often clear up on their own in a day or two. Cold hosing and washing down with a diluted solution of baking soda in water may help with the swelling and itching. More serious cases may require a visit from your veterinarian and treatment with anti-inflammatories or antihistamines, especially if breathing or digestion is affected. If your horse has serious or repeated episodes of hives, talk to your vet about allergy testing to determine the cause.

Melanomas and Sarcoids

A melanoma is a firm, round nodule containing a black or dark brown pigment called melanin. They can develop anywhere, but are usually found under the root of the tail, around the genitals, at the base of the ears, around the eyes or in the throat region. They are most common on older, grey horses. The underlying cause is not known, although it is believed to be linked via genetics to coat colour, and that sunlight could be a factor.

There are two types of melanoma: benign and malignant (cancerous). Benign melanomas grow very slowly, whereas malignant tumours grow much more quickly and can spread to other parts of the body, including internal organs. Treatment can include cryotherapy (freezing), medication, and surgical removal of the tumour. Your veterinarian can perform a biopsy (removal and examination of a tissue sample) in order to learn what kind of tumour it is.

Sarcoids are commonly-seen tumours beneath the skin, believed to be caused by bovine papillomavirus and spread by flies or even shared tack. They are most often seen around the eyes and ears, or on the legs and abdomen. While rarely deadly, they are unsightly and hard to get rid of. (See also ‘Skin Tumours: Not your Ordinary Bumps’ in the Nov/Dec 2012 issue of Horse-Canada).