Skin diseases in horses – Equine Sarcoids - Horseback Riding worldwide

The skin is the biggest organ of the horse. It is the direct contact with the horses’ environment and can easily be irritated by many different triggers.

In general the horse can suffer from many different kinds of skin diseases. The Equine Sarcoid is the most frequently diagnosed cancer tumor in horses.

Many horse riders try to avoid any conversations about skin diseases. At first they are only an “aesthetic problem” that does not influence the physical power and therefore the training of the horse. If any other member of the stable points out that there is a change in the horses´ coat or skin many horse owners want to be blind and contradict all possible allusions. No one in the stable wants to have a horse with a skin disease because other horses easily can be infected. Finding a new shelter can be cost- and time intensive and every horse owner wants to avoid this situation. As soon as the skin disease begins to affect the area of the saddle or the track a further denial is impossible and the horse owner needs to start with the therapy. Then, however, it can already be too late because the tumor already spread over the whole body. This clearly limits the cure possibilities and therefore the chance that the horse owner can ever ride his horse again.

Equine Sarcoid – a skin tumor that occurs in different types

1-8% of all horses suffer from the skin tumor Equine Sarcoid (ES). It is a benign tumor because it normally stays on the skin and does not spray into the interior organs of the organism. At the beginning Sarcoids very often get mixed up with warts. Sarcoids can appear in six different types each one with its own characteristics. Generally, all horses of any species can be infected by this skin tumor. Some research studies found out that especially young horses in the age between three and seven are in danger of this dangerous disease.

Causes of an Equine Sarcoid

Many horses carry the virus in their organism. The trigger of the tumor is the Bovine Papillomavirus (BPV) Typ I or Typ II. Until today scientists did not find out how the horse gets infected with this virus. Some studies suggest that a Sarcoid often occurs after an infectious disease, a worm infestation, a non species-appropriate husbandry or stress.

Shapes and sizes of Sarcoids

The skin tumor can appear sporadic or all over the horses´ body. Especially thin and sensitive skin areas such as the face (most of all the eyes and ears), mucous membranes, the shoulder, the inside of the legs, the genitals and scarred tissue can be infected by the tumor. Sarcoids can grow in six different types that differ in their outwards appearance and their degree of aggressiveness.

Occult Sarcoid

Most frequently an infected horse first exhibits the symptoms of an occult Sarcoid. This type only has a low aggressiveness. The horse has flaky and bald patches on his skin. These symptoms can easily be mixed up with a simple abrasion or an allergic reaction. In many cases horse owners do not even recognize this change in the coat of the animal and do not start with the respective therapy. This can lead to the fact that the tumor becomes more aggressive and continues to grow or even spread on other parts of the body.

Verrucose Sarcoid

The Sarcoid appears in form of warts. Especially the eyes and the belly of the horse are infected. Some warts are slightly crusted. Verrucose Sarcoids can become very aggressive until they finally reach the size of a fist.

Nodular Sarcoid

During the daily grooming the horse owner can notice small lumps underneath or on the skin of the animal. This form of skin cancer can become very aggressive and spread all over the skin.

Fibroblastic Sarcoid

A tumor of one of the three types described above can become more aggressive. The correlated growth process can finally lead to a fibroblastic Sarcoid. Indeed, seeing this tumor can be nauseating because it looks like a bloody ulcer that grows out of the skin.

Malevolent Sarcoid

This type of the skin cancer is a malignant tumor because it also attacks the interior organs (especially the lymphatic vessels). But even if only few horses suffer from this type of Sarcoid it is very aggressive and can become a serious health problem.

Mixed Sarcoid

In this case the Sarcoid is a mixture of at least two of the other tumor types described above (especially pedunculated tumors that are slightly crusted and horny).

An early diagnosis requires an attentive horse owner and increases the cure possibilities. The daily horse grooming is more than just a quick cleaning process. Instead this time needs to be used for a detailed control of the horses’ body. Then horse owners can also discover little changes in the coat and on the skin and directly start with an effective therapy.

Diagnosis and therapy of an Equine Sarcoid

A skin tumor can cause serious problems of the horses’ health and therefore limit the physical power. In worst case it can even become impossible to continue to ride the horse. However, the course of the disease can be influenced positively by an attentive horse owner and an early diagnosis. As soon as there are the first patches on the skin the horse owner needs to identify if they possibly come from a normal abrasion. If not, the horse owner needs to contact a vet. With the help of a biopsy the vet is able to make an exact diagnosis. For the biopsy he takes off a tissue sample and sends it to a special laboratory for the detailed examination. Still there are controversial opinions about a biopsy: often the regrowth of the tumor occurs more aggressively.

The type of therapy is dependent on the respective infected body part and on the type of the tumor. Today there are already a lot of different therapy programs. However there are very controversial discussions about the respective effectiveness. The horse owner should only start a therapy after a detailed consultation with the vet. A skin tumor is a very complex disease and in worst case it can even lead to death. Only a vet is able to make an exact diagnosis, to identify the type of cancer and then to decide about the best therapy.

Possibilities for surgical excision

The standard therapy for a Sarcoid is a surgical excision. During the surgery the vet removes all infected tissue. But even if there are no problems during the surgery there often are post-surgery complications. Many scars become inflamed or are infected with other dangerous and painful infectious diseases. Sometimes the tumor already spread in the whole organism. In this case it is impossible to remove all infected tissue so that soon a new tumor begins to grow. Very often a freeze therapy leads to a great success. The tissue gets frozen until it finally mortifies and literally falls off. But also this therapy does not guarantee that there is no regrowth of the tumor. Further possible treatments are chemotherapy and electrosurgery (with the help of electric the tissue gets coagulated). The highest chances of success are provided by radiation therapies with a success rate of 80-90 %. However, only a continuous therapy can be successful and the horse owner needs to be aware of the high costs that come along with this treatment.

Alternative therapies: banding, injection, ointments, homeopathy

Before taking the risks and costs of a surgical excision, the horse owner can first try out several alternative therapy forms. For the first step many vets advice to band the tumor with rubber rings. This stops the blood supply of the tissue until it finally mortifies and literally falls of. A further possibility is an injection with Bacillus Calmette-Guérin as an immunomodulator (normally this vaccine is used for the prevention of tuberculosis). Additionally more and more horse owners share their positive experiences with the American ointment XXTERRA. This ointment is made out of tetterwort and a zinc paste. First you administer the ointment for 4-6 days. This normally leads to a light inflammation of the tumor. Then you need to stop the treatment for 4-6 days. It is crucial that you do not wait longer than 6 days. Otherwise the entire healing process is disturbed and the therapy will not lead to any success. The horse owner needs to continue with the therapy until the tumor finally falls of the horses´ body. At its place there will be a wound that requires the normal medical treatment. In many cases this wound completely heals after 2-3 months. But even if this ointment already is quite successful in the United States it still is very difficult to buy the product in Europe. In many countries only vets are allowed to buy the medicinal ointment.

Further possible medicinal ointments that already lead to a great healing process are the Liverpoolcreme and CompX. In many cases both products lead to a success of the therapy. Additionally the horse owner can already try out homeopathic treatments (a specialist analyzes the entire environment of the horse including feed, husbandry, etc.).

Watch out for self made ointments! In some internet websites you can find recipes for self made ointments. Some ingredients (e.g. zinc sulfate) in a wrong dosage can easily lead to a great damage and an even worth health situation of the animal!

Healing possibilities of a Sarcoid

As a general rule every horse owner needs to consider that every horse reacts in a different way. If one medicinal treatment causes a great healing success in one horse this does not guarantee the same course for another horse. In many cases only a mixture of several different therapies leads to a lasting success. Many therapies take a long time and are characterized by demotivating regrowths of the tumor. Therefore the most important requirement for a successful therapy is discipline and endurance of the horse owner.

Only a vet can decide about the correct therapy for the horse. Doing something on one´s own can cause more harm than good!

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