Skin deep
Sarcoids are common in horses but can be unpredictable and hard to treat, as vet Ralph Maalouf explains
Photos: Adam Fanthorpe, Jon Stroud. Patricia Barker, Chella129, Miriana Stumpf Linck/shutterstock.com. With thanks to VetPartners practice, New Era Veterinary Hospital, for their help with this feature neweravets.co.je, vetpartners.co.uk. Photos posed by models.
Our expert
Ralph Maalouf DVM MRCVS CVA MBA is an equine vet at New Era Vets on Jersey. He has a special interest in equine emergencies and orthopaedics.
Acommon, yet challenging, skin condition, sarcoids affect horses of all ages, colours, and breeds, and are often a cause for concern among owners and vets due to their unpredictable behaviour and unreliable response to treatment.
Sarcoids make up approximately 90% of all skin tumours in horses although, fortunately, they’re benign in nature, being composed of fibrous connective tissues. They can, however, be unsightly or a nuisance if they develop in sensitive areas or where tack or equipment sits.
Contributing factors
The exact cause of sarcoids in horses remains unknown, but several factors have been proposed as contributing to their development. These are mainly associated with immune function, but environmental and genetic factors also seem to play a role in sarcoid development...
• Bovine pappilomavirus infection (BPV) has been strongly associated with the development of sarcoids. It’s a condition affecting cattle, but horses may contract the virus by direct contact with infected animals or via contaminated equipment
• Genetic susceptibility may play a part, as not every horse infected with BPV will develop sarcoids. Similarly, there’s some evidence to suggest certain breeds are more susceptible
• Environmental factors, including UV exposure, may play a role in triggering sarcoid growth on areas of the horse’s skin that are more frequently exposed to sunlight
• Trauma and injuries to the skin in certain areas may trigger the formation of sarcoids, although sarcoids also develop at non-trauma sites