Ringworm in Horses

Light micrograph of the fungus
Micrograph of tinea causing fungus.

CNRI/SPL / Getty Images

Ringworm in Horses

There are lots of things that you’d like to share with your horse. Ringworm isn't one of them. This dermatitis can affect all kinds of creatures — dogs, cats, horses and of course, people. Thankfully, although it looks unsightly, and your horse may be uncomfortable for a bit, ringworm is pretty easy to treat and if treated promptly, is yucky but not very harmful. If you do happen to get it, it's easy to clear up. 


Ringworm, Tinea or Dermatophytosis in horses.


The name ringworm suggests that this form of dermatitis on horse's is caused by a worm. In fact, ringworm is caused by fungus. It has nothing to do with worms, internally or externally. Ringworm fungi like to live on the warm, moist surface of your horses skin and hair. The really bad news is that ringworm is not choosy about who or what it lives on. Ringworm is a zoonotic disease, and it can be transferred to any of your human or animal family members. Without proper hygiene procedures, ringworm can be transmitted quite easily. The medical name for ringworm is Dermatophytosis or Tinea. Youngsters, senior horses and horses in poor condition are more likely to be affected. Do not confuse ringworm with roundworms, which are an internal parasite that are best controlled with a parasite control schedule.


Ringworm on horses may first appear as circular patches of hair. The hair in the center of the patch will fall away, leaving the typical circular lesions that give the skin condition its name. The lesions may appear first in the saddle and girth area, where the skin stays damp longer and the contact makes it spread more easily. The hairless patches may appear inflamed and encrusted with flaky skin. Ringworm may start out as only one or two patches but quickly spread. This is one time grooming is not recommended as brushing may spread the fungus to other parts of the body.


While a horse with ringworm may be uncomfortable, ringworm is really more of an unsightly nuisance than any sort of harm. Ringworm may disappear on its own weeks or months after the initial outbreak. But in the meantime, ringworm can spread to other horses, cattle, humans and pets as the fungus can persist on stall walls, brushes, tack and other items the horse may come in contact with. A horse with ringworm will not be welcome at shows or other events. That is why most people opt to treat the condition to help it heal faster. Once a horse has had ringworm, it is unlikely it will get it again.


The lesions caused by ringworm are typical enough that the skin condition can be diagnosed by eye. But if there is any question, your veterinarian can take a skin scraping and examine it. Then the horse will be treated with anti-fungal wash. Some vets may suggest shaving the area. Because the fungus will persist on the horse's brushes, tack and stable, all must be washed down with an anti-fungal solution to prevent further spread. It's important to wear gloves during the treatment time and take care not to pass the fungus on to other people or animals. Some people have had good results with natural remedies that contain ingredients like tea tree oil or solutions that contain iodine.


Keeping your horse in good health is the key to avoiding many problems. It is a good idea for each horse to have its own tack and brushes. If ringworm is suspected, the horse should be kept away from others until the lesions disappear. Any new horses brought into a stable should be carefully examined and kept separate if there is any health concern. Good hygeine will help prevent spread of the fungus. 

Be sure to wash your own hands, and clean your clothes and boots after treating or handling a horse with any skin problems.