Just like humans, horses can also develop warts. Warts, also called papillomas, are caused by a virus and are usually found in young horses because they have a decreased immunity that plays a role in this syndrome. It is common to see warts on the nasal area and around the eyes as well as around the prepuce on male horses. Sometimes warts can develop on the lower legs or on the inside of the ears. Warts are contagious, especially to other young horses, by direct contact but the virus can also be spread by flies. In almost all cases, warts are considered a self-limiting condition. This means that as the horse gets older, immunity develops and the warts will fall off without any treatment. Depending on the horse's age and immunity, this may take 3 to 6 months.
Removing the warts is usually not recommended unless they are causing a problem such as eating or lameness. If there are only a few warts, removing them surgically is reasonable but in most cases there are too many warts for surgical removal. Human wart medications have been used in horses and are said by some to be effective. However, they are not approved for use in horses so I would be careful using human products. It has been believed for years that crushing a wart with a forceps and actually feeding it to the animal acts like a vaccine and causes the warts to fall off. Although this has been commonly done, there is no evidence that the technique really works. Although wart vaccines are available for cattle, there are no vaccines approved in horses. Unless the warts are causing a problem, it is best to leave them alone and let them fall off naturally.