How to Treat Ringworm in Horses

Your horse’s haircoat looks scruffy along one side of his neck. On closer inspection, you see patches of hair loss. The exposed skin is crusty with large flakes of dandruff (dry scales). There’s no evidence that the affected area is inflamed or itchy. That is, the skin isn’t red or hot, and there are no scrapes or scabs that would suggest he’s been rubbing. He doesn’t seem to mind when you touch the exposed skin, and you’ve found no similar lesions elsewhere on his body. He appears healthy in all other respects

What Should You Do if Your Horse has Ringworm?

1. Call your veterinarian as soon as you can.

Why: Although this isn’t an emergency requiring immediate veterinary care, you should inform your vet about your horse’s condition. Although the lesions are probably caused by a local fungal infection (more about that in a minute), they might signify something more serious (such as a body-wide infection), requiring veterinary treatment. By calling your vet now-and providing updates throughout your home- treatment program-he or she will be able to determine whether veterinary treatment is called for.

Most likely, the lesions are caused by ringworm, a fungal dermatitis, or fungus-based skin infection. (Fungus refers to organisms whose goal is to destroy organic-or living-material.) The lesion appears to be superficial and limited to one area of your horse’s body, so it should respond well to home treatment.

2. Clip hair away from the affected area.

Why: To remove the fungus’ main food source: keratin, the protein that makes up your horse’s hair and outer skin cells.

Using electric clippers and a #40 (surgical) blade, clip any remaining hair from each bald spot. Extend the shaved area so there’s a 1/2-inch margin of unaffected skin around each lesion.

3. Spot-bathe the lesions.

To help kill the fungus.


  • Wet the shaved area with a sponge, and apply antifungal antiseptic, such as Betadine scrub, available at pharmacies, or Novalsan scrub, available by prescription from your vet. Lather up the scrub, and let it stand for 10 minutes to give it time to thoroughly kill the fungus.
  • Rinse thoroughly with water.
  • Follow with a final rinse, using 2 tablespoons white vinegar mixed in 1 quart of clean water. This solution helps cut any remaining soap and creates a slightly acidic environment unfriendly to fungi. Apply the vinegar solution to affected areas with a sponge or trigger-type spray bottle.
  • Blow-dry the wet areas-especially in cold weather-if you have access to electricity in your barn. Otherwise, towel-dry the areas the best you can, then let them air-dry.

4. Apply an antifungal dressing.

Why: To kill any remaining fungus on the skin, and to discourage new infections.

How: Apply a thin layer of antifungal ointment or spray, such as Betadine ointment or an over-the-counter human product for athlete’s foot. Repeat daily for 7 days, then reduce to twice a week until the lesions appear to be shrinking and new hair growth is visible in their centers (about 1 to 2 weeks)

5. Keep lesions clean, dry, and exposed to air and sun.

Why: Fungus thrives in dark, damp conditions, such as the deep recesses of a wet, dirty winter coat. Dry conditions and ultraviolet light (sunlight) kill fungus.

How: If your horse gets wet and/or dirty, use clean grooming tools to remedy the situation, and provide clean, dry living quarters. On clear, sunny days, turn him out in a dry paddock where his skin can get a good dose of sunshine. Don’t blanket him if you can avoid it. If you must (i.e., if it’s bitterly cold), use a clean, dry garment that isn’t shared with other horses. (For why, see below.)

6. Disinfect your premises and yourself.

Why: Ringworm is contagious to horses and other livestock, house pets, and humans.

How: Clean up all clipped hair and grooming debris in the treatment area, and discard them in a knotted plastic garbage bag. Thoroughly clean grooming equipment in Lysol disinfectant concentrate, rinse, and allow to dry. Bathe and shampoo yourself and any house pets that may’ve come into contact with these materials. Launder your clothes. Check yourself, family members, and other animals for lesions once weekly for the next 3 weeks.

7. Evaluate your horse’s progress.

Why: To determine whether your home treatment is working. If you follow the above instructions and there’s no improvement, your horse may have an underlying problem that will require veterinary evaluation and treatment, and/or the fungal infection may be deeper and more severe than home treatment can resolve.

How: Once a week, check for new lesions, and examine existing lesions to see whether they’re shrinking and growing new hair in their centers. If there’s evidence of spread, and/or if there’s no improvement within 2 weeks, call your vet for an evaluation.

Prognosis is excellent. Most cases improve quickly with treatment and good hygiene.

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