Sunburn or Photosensitivity in Horses

Causes, Treatment, and Prevention

white horse in a field
Barrett & MacKay/ Getty Images

Especially in the summer season, humans and animals alike can experience sunburn. Despite our best efforts to apply plenty of sunscreen and stay in the shade, this condition affects many of us from time to time. Horses are no different, but when it comes to the equine world, sunburn is usually most severe on the nose. Your horse may also experience burns on its back, face, ear tips, and white areas on the legs. Horses with white coats (whether entirely white or in patches on the body) are more susceptible to burns. Some may experience a condition with similar symptoms called photosensitivity caused by the ingestion of certain plants. Sunburn usually resolves on its own, but a variety of treatment options can help ease your horse's symptoms.

What Is Sunburn?

Sunburn occurs because of overexposure to ultraviolet (UV) light, which typically causes symptoms like redness, inflammation, and pain. Horses with unpigmented patches on their bodies are more likely to experience sunburn than those with darker coats, noses, and legs. Lesions from burns typically affect parts of the body that come into consistent contact with direct sunlight like the nose and face.

Symptoms of Sunburn in Horses

Horses experience similar symptoms of sunburn to those seen in humans. Like the red, irritated areas on your own skin during the summer months, you may observe the following signs of sunburn on your horse:


  • Red skin
  • Inflammation
  • Blistering and peeling
  • Pain

Red skin and inflammation are both common signs of sunburn, although horses may also experience blisters, peeling, scabs, and cracked skin in more severe cases. This is usually limited to the face and nose, but horses that are thin-coated or have pink skin may also become sunburned on their backs. Most commonly, horses with white or pink noses (like grays or pintos) experience sunburn. In some cases, burns can also occur along the protruding areas of the face, ear tips, and white leg markings just as human noses, ears, shoulders, and collarbones get burned from direct exposure to the sun.

Causes of Sunburn

While exposure to the sun during the hottest parts of the day may be enough to cause a sunburn on your horse, photosensitization can also lead to burns when your horse ingests certain plants. The following causes of sunburn and photosensitivity may occur:

  • Overexposure to the sun: Ultraviolet light from the sun causes sunburn on humans and many animals when overexposed. If your horse enjoys spending time in the pasture or other areas with direct light, it's best to limit these outings to times of the day when the sun isn't as strong.
  • Photosensitization caused by plants: There are a number of plants that can cause photosensitivity in horses. St. John's Wort affects horses and cattle with this condition. Other plants like buckwheat and ground elder (also known as snow-in-the-mountain) can have this effect. One species, alsike clover, can cause photosensitivity as well as liver failure, gastric problems, and neurological disorders. This is called secondary photosensitization, and byproducts from chlorophyll in some green plants are the reason that exposure may cause liver problems.
  • Topical treatments and medications: Some grooming sprays or fly sprays may exacerbate a sunburn. Photosensitivity may also be caused by some medications, so owners should consult their equine veterinarians about safe choices for horses in direct sunlight.

Diagnosing Sunburn in Horses

If your horse experiences a normal sunburn that is not linked to photosensitization, your veterinarian can diagnose the condition during a standard physical exam. However, the signs of photosensitization are similar to those of standard sunburns, and a veterinarian should be consulted to determine the underlying cause of your horse's symptoms. Photosensitization may indicate the presence of liver diseases that require further diagnosis. Your equine veterinarian may perform liver biopsies and an evaluation of the liver enzymes along with screening your horse's blood, feces, and urine.


When it comes to sunburn, treatment options are somewhat limited but typically involve management of symptoms until your horse comfortably recovers. If sunburn affects the back, riders should avoid riding until the burn heals to avoid putting a saddle on top of a painful burn. Any areas of your horse's skin that become cracked or scabbed should be removed safely to prevent infection. Equine owners can apply topical antibiotic creams like Flamazine to soothe uncomfortable areas on their horses before treating minor wounds.

If your horse is experiencing photosensitization, it should be stabled during the day and only allowed out at night until severe symptoms have resolved. Because this condition can cause skin tissue to die off, your veterinarian may recommend corticosteroid injections along with preventing flies from affecting your horse.

Prognosis for Horses With Sunburn

In most cases of sunburn, your horse can recover without much intervention. Limiting its exposure to the sun is key, as an already burned horse can experience more severe burns if allowed in direct sunlight before healing completely. The prognosis for horses with liver disease leading to photosensitivity will depend upon their specific condition, which a veterinarian can determine. Extreme cases of photosensitization can be fatal when a horse undergoes excessive loss of healthy skin tissues—so owners should utilize all available treatment methods to allow for a safe recovery. Thankfully, most horses with photosensitivity issues can return to a healthy state after treatment.

How to Prevent Sunburn

Sunburn can be very uncomfortable, but thankfully, there are several methods equine owners can use to help keep damaging rays from the sun away from their horses:

Avoid Peak Daylight

Preventing sunburn most often means keeping them out of the sun when it's at its strongest. It's important to provide a shady place such as a line of trees or run-in shelter. Some people choose to . This is a strategy used to prevent show horses from getting sun-bleached coats.

Apply Sunscreen

Baby formula sunblock can be used to protect your horse's vulnerable areas. Your horse will have its head down to graze, so the product will wipe off quickly and need to be reapplied frequently. Products made specifically for horses are brightly colored so owners can see when they've worn off. This might not be the best idea if you're heading to the show ring, however. Inexpensive zinc oxide paste is useful in your equine first aid kit as both sunblock and to help heal any previously irritated skin.

Fly Sheets and Masks

Fly sheets and masks can help prevent sunburn on your horse. A full mask such as the Absorbine Fly Shield covers your horse from the top of its nose to its ear tips. Pale-colored fly and sun sheets give horses a little protection over their backs. Because these sheets are made with mesh (however, they shouldn't be considered total protection, as some sun rays will get through). Be sure that sheets fit well. A poorly fitting sheet can be irritating, especially over the shoulders and withers.

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. How can I protect my horses from sunburn? Ridings Equine Vets.

  2. Summer Care for Horses. University of Florida Institute of Food and Agricultural Sciences.

  3. Photosensitization in Horses. Merck Veterinary Manual.