Your guide to sarcoids in horses

While taking care of your horse, sorting their feed after a nice walk in the sun you notice some changes on their skin. It could be rough, scaly or, if you’re quite late to spot them, bulbous tumours hanging from them. That lump, scaly patch or skin condition could be sarcoids and if you’ve found this blog because you’re concerned about your horse, read on to get a good understanding of what they are, what to do and how to best take care of a horse with equine sarcoidosis.

Further from this, you’re welcome to call our advice line on +44 1243 773 363

What are sarcoids?

They’re the most common type of skin tumour found on horses and other equid species across the globe. They have a wide range of appearances, developments, and characteristics which make each variation slightly different and challenging for veterinary hospitals to treat.

Many horses continue to have them after unsuccessful treatments, the success rate can be disappointing with current offerings.

They can develop anywhere on the body but are most commonly found in specific areas, including:

• The eyes / eyelids / ears
• Muzzle/lips
• The chest and axilla (armpit region)
• The sheath and in between the back legs

What causes sarcoids in horses?

They’re a common skin tumour believed to be caused by the bovine papilloma virus (BPV), but it appears that it requires genetically susceptible horses in order for the development of sarcoids as not every horse exposed to BPV will go on to develop tumour cells.

It’s possible that they spread contagiously but, as yet, the ability for sarcoids to be passed on by flies or direct horse-to-horse contact is unproven and there is no current evidence that horses affected by sarcoids are a threat to other horses developing them.

Equine Sarcoid Types

Sarcoids are locally invasive tumours but don’t commonly metastasise (spread around the body) and are grouped into 6 broad categories.

Types of sarcoids in horses:

Occult sarcoids: a flat patch of hair loss with a grey, scaly surface.. These are a less obvious form of sarcoid are often confused with ringworm. This is often due to the fact that they have an annular (circular) lesion shape to them. Commonly seen on the face, neck and between the back legs, also known as ‘flat sarcoids.’

• Verrucose sarcoids / verrucous equine sarcoids: wart-like, grey and scaly but goes deeper than occult sarcoids in horses and have a more irregular appearance
• Nodular sarcoids: lumpy ‘grape-like’ lesions. These can vary drastically in size and number and are most commonly found around the groin and eyelids
• Fibroblastic: A Fibroblastic sarcoid can be quite aggressive in nature and can develop and alter rapidly. They are commonly fleshy masses that bleed easily and have ulcerated surfaces that stand out a mile from normal skin. They look like proud flesh and can often develop at the site of a wound. These can be found anywhere on a horse body and can develop from the less aggressive types such as verrucose and nodular.
• Malevolent sarcoids: this is the most aggressive type of sarcoid, it can spread and grow rapidly, and usually looks like a group of ulcerated, nodular type lesions. These are so aggressive that often there are no treatment options but thankfully they are rare.
• Mixed: this describes a sarcoid/group of them that show qualities of two or more of the classifications

They can appear as single lumps that can vary in size from a pinhead to a small melon, or as clumps of more than one. The skin on horses with sarcoids is often fine for a while but can become ulcerated as it continues to grow and develop which can then lead to infection and complications. They can be especially frustrating to deal with during the summer due to flies and can eventually become non-healing sores.

Sarcoid Treatment

Sarcoids are a serious problem and even the appearance of a single tumour should be taken seriously, its presence could lead to many more over time. Early treatment of equine sarcoids is always more effective, and currently, it would appear the treatment at under 4 years of age gives a slightly better prognosis. Treatment will depend on the size, location, number and type of lesion present, and there is no one sure-fire way to deal with all types of sarcoids. Sarcoids also have a high tendency for recurrence despite effective treatment.

Medical Treatment for sarcoids:

• The immune stimulant Bacillus Calmette Guerin (BCG) vaccine (which is used to prevent Tuberculosis in people) is injected into the sarcoid itself
• The injectable chemotherapy drugs cisplatin and Mitomycin C acts by interfering with DNA replication in the cells

Sarcoid creams for horses

• Photodynamic treatment in which a chemical is applied to the surface of the tumour and then exposed to a specific type of light that activates the chemical and kills the cancer cells
• A topical treatment cream AW4-LUDES (‘Liverpool cream’)
• Bloodroot ointment cream

Surgical treatments include:

• Surgical excision
• Laser Surgery
• Cryosurgery
• Ligation and banding of nodular lesions

Surgical excision without additional therapy may not always yield the best results, these can be improved by following them up with cryosurgery or other treatment options but can often lead to a fairly high recurrence rate.

Radiotherapy: local radiation has shown good results but is highly expensive. Iridium192 wires are used to deliver a radiation dose straight into the tumour itself. This means that it can be used in delicate areas (e.g. around the eyes) as it limits damage to neighbouring and deeper tissues. It can only be carried out at certain licenced premises.

Natural treatments for sarcoidosis include:

Keeping your horse at optimal health with exercise, adequate nutrition and supplementation or dietary support.

Sarc-Ex is an advanced and unique formula that provides nutritional support for the immune system of horses. The strong antioxidant herbs help the body cope while maintaining normal structure and function.

Should I buy a horse with sarcoids?

So long as you understand what you’re dealing with and can adequately care for a horse with sarcoids. It’s worth taking note that horses that are found to have them at a pre-purchase exam (vetting) will be excluded by insurers. This is because it’s a pre-existing condition and treatment can be costly to treat.

Take-Home Messages

1. Sarcoids are persistent and progressive skin tumours of all equid species (including donkeys and zebras) that are locally invasive but rarely metastatic.
2. They are developed in response to exposure, in genetically susceptible horses, to BPV
3. They can occur anywhere but are commonly found on the head, chest, and groin
4. There are various types that each has their own characteristics and qualities and can require different approaches when considering equine sarcoid treatment options
5. Horses that are found to have sarcoids at a pre-purchase exam (vetting) will have them excluded by insurers as a pre-existing condition and treatment can be costly