Papillomas in Horses

Causes, Treatment, and Prevention

bumps on horse's nose

Rollover / Getty Images 

Papillomas can appear overnight on your horse's skin. But there's no need to sound the alarm if you find grayish or skin-colored bumps on the nose of your young horse. Papillomas may look unsightly, but they shouldn't cause excessive worry and are more of a nuisance, especially when you want your horse to be well turned out for the ring.

What Are Papillomas?

Papillomas refer to small, gray, irregular bumps on your horse's skin that look like warts. Some smaller warts, called baby warts, are also sometimes referred to as "teenage acne" in the horse world. They are most commonly seen on a horse's nostrils and muzzle or on thinly-haired areas of its body (such as the eyelids, or front legs).

warts on a horse
The Spruce / K. Blocksdorf

Symptoms of Papillomas in Horses

Viral papilloma can pop up quite suddenly. One day, your horse seems fine; and upon further inspection, you find strange bumps that seem to spread easily and almost overnight. Here are the two obvious symptoms of papillomas in horses.


  • Cauliflower-like bumps
  • Cracked, bleeding skin

Cauliflower-Like Bumps

A whole region on your horse may look encrusted with clusters of unattractive cauliflower-like bumps that are small flattened or raised ovals with a somewhat hardened and sometimes crusty surface. These bumps can show up on the face, ears, legs, and genitals.

Cracked and Bleeding Skin

It's also not unusual for the skin to crack and bleed, or for papilloma warts to break off in areas that are mobile, like on the lips and nose. Some horse owners believe that once they bleed and scab, the warts will go away faster. However, any open wound must be closely monitored to prevent infection.

Causes of Papillomas 

Similar to the warts humans contract, horse papillomas are caused by the equine papillomavirus, a herpes virus, resulting in a viral infection. When papillomas are present on the ears, they are called aural plaques. These flaky, crusty parts of the horse's skin are spread by flies who carry the papillomavirus.

Diagnosing Papillomas in Horses

Since warts are common, most seasoned horse owners can diagnose an outbreak without the help of a veterinarian. But for questionable lesions, a veterinarian can take a biopsy to make sure the bumps aren't sarcoids (a type of skin tumor) or another type of infection or tumor.


On young horses, treatment is not necessary since papillomas will go away within a few months as the horse develops its own resistance to the virus. It's almost as if the warts disappear as mysteriously as they come. If the affected area becomes inflamed and sore, you can try to make your horse more comfortable with the following home treatments:

  • Keep the affected skin clean of dirt and grime.
  • Treat inflamed or sore spots with over-the-counter antiseptics or a topical moisturizing lotion for cracked skin.
  • If your horse becomes uncomfortable, try diaper rash ointment on the bumps. It is harmless to your horse.

It's also fine to simply let the papillomas outbreak run its course. If you are concerned that your horse is uncomfortable or that an affected area might be infected, call your veterinarian for advice. In extreme cases, the papilloma may need to be surgically removed if it is not healing.

Prognosis for Horses With Papillomas

Papillomas are non-fatal to horses. It may sometimes be best to let the breakout run its course, as warts are rarely painful. Outbreaks will typically disappear as your horse continues to thrive and mature.

How to Prevent Papillomas

Other than basic stable hygiene, there's little that can be done to prevent horses from contracting warts. However, here are three important steps to take to contain an outbreak:

  • If one horse has an outbreak of papillomas, keep it quarantined.
  • Practice using separate water buckets, feed bins, and other equipment for each horse to prevent the virus from spreading. Sometimes the virus may be present before you see the signs, however, so this precaution may not be entirely effective.
  • After an outbreak, disinfect all the barns, feeding troughs, buckets, and tack to kill lingering organisms. A diluted bleach solution can be used on feeding equipment and stall walls. Use soap and water to scrub down tack.

Are Papillomas Contagious to Other Animals?

These warts are contagious to other young horses but will resolve on their own in one to nine months without treatment. Nonetheless, watch your other horses closely, as other young horses in the same pasture or barn may break out, as well. Here are a few ways papillomas can spread:

  • A young mare can transfer these equine warts to her foal as it nurses.
  • Young horses can also catch the virus from affected buckets, fences, or any other place a curious young horse may stick its nose into or brush up against.
  • Papillomas mostly affect horses less than 18 months old, and it is very rare—yet, not impossible—for an older horse to get them. Though older horses rarely get warts, finding lumps and bumps in mature horses can be signs of other problems.

Are Papillomas Contagious to Humans?

This type of wart is not zoonotic (a disease that exists in animals but can be transferred to humans), so you don't have to worry about contracting the virus from your horse. And certainly, you cannot make your horse sick either.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.
Article Sources
The Spruce Pets uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Skin Diseases Refresher Papillomatosis (viral warts). American Association of Equine Practitioners. 

  2. Skin Diseases Refresher Papillomatosis (viral warts). American Association of Equine Practitioners. 

  3. Skin Diseases Refresher Papillomatosis (viral warts). American Association of Equine Practitioners.