What you see. The starting point for addressing any equine health related issue is your observation.


Sores, Crusts, Scabs or Peeling on White Areas of Face


Peeling and crusting of the white areas on a horse's face can result from a simple sunburn or windburn. But this could also be photosensitization, which is a distinct disease process that may need to be treated differently.

Photosensitization is severe sunburn caused by interaction of ultraviolet light with specific molecules in blood or skin. These molecules come from certain feeds. The problem can also occur when liver dysfunction allows the levels of certain sun-reactive plant pigments to increase in the tissues. Horses with liver disease are usually depressed and have reduced appetites.

  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If this problem seems severe and has come on suddenly.
  • Code Green

    Contact Your Vet to Obtain Useful Advice & Resources
    • If this is the only sign you notice. The horse seems well to you otherwise.
    • If the problem seems very mild and limited to a small area.

your role


What To Do

You can treat reddened skin on the face symptomatically with sunscreens and zinc oxide, but understand the need to differentiate between possible disease processes. Prevent additional exposure to the sun by covering the affected area of your horse's face with a face mask and a muzzle extension, if necessary. Assess the horse's general health using the Whole Horse Exam (WHE), paying particular attention to the rectal temperature, the appearance of the gums (look for a yellow shade), general attitude and appetite.

Consider whether the horse's diet or management has changed. Some hays are photosensitizing. Horses on certain types of pasture are more at risk for photosensitization. Share your findings and management with your vet.

What Not To Do

Do not apply ointments or salves without sunscreen unless instructed by your vet. They may make the problem worse.

your vet's role

Through examination and blood work, your vet can help differentiate simple sunburn from more serious photosensitization.
Questions Your Vet Might Ask:
  • Is the horse kept on pasture?
  • Do you notice any other white areas affected?
  • How is your horse's attitude and appetite?
  • When did you first notice this?
  • Are other horses in the group affected?
  • Has your horse lost weight?
  • What does the horse eat?
  • Do you notice yellowish gums, skin or whites of the eyes?
  • What are the results of the Whole Horse Exam (WHE)?

Diagnoses Your Vet May Consider

The cause of the problem. These are conditions or ailments that are the cause of the observations you make.

Very Common
Less Common
more diagnoses

further reading & resources

Author: Doug Thal DVM Dipl. ABVP