How to Treat Ringworm in Horses
Table of Contents
What is Ringworm?
Ringworm presents as a scaly, dry, hairless patch of skin usually circular in shape. It is caused by a fungus, not a worm or parasite as the name may imply. While the horse’s immune system could naturally clear up the infection in a few months, treatment is highly recommended to expedite the healing process and minimize the risk spreading to other animals.
Ringworm is Extremely Contagious
Highly contagious, ringworm can be spread through direct contact or via objects such as brushes, blankets, or stall walls. The fungus is highly resilient and can live for months on a given surface. The main treatment for this skin condition is bathing—both the infected animal and anything that animal may have touched.
Why does my Horse have Ringworm?
Ringworm affects the horse’s skin and is not caused by a worm or parasite at all— it is actually caused by a fungus. The name “Ringworm” comes from the round, raised pattern that appears on the skin of the affected animal. The more scientific name is Dermatophytosis, or Tinea.
There are several different species of dermatophyte fungi that can affect horses; Microsporum and Trichophyton. Trichophyton equinum is responsible for most cases of equine ringworm6. Unfortunately, ringworm can be transmitted between horses and to other animal species, including humans.
Ringworm needs to be Treated
Highly contagious, ringworm should be taken seriously and treated immediately. Without treatment, horses will generally recover in a few months; however, treatment is recommended both for the horse’s comfort and to prevent the spread to other animals.
What Causes Ringworm?
Ringworm is the most common fungal skin infection found in horses. It is caused by a dermatophyte fungus, presenting as a skin lesion that generally causes hair loss and round, scabby patches. It’s important to note that the lesions don’t necessarily have to be round—a circular shape is just most common.
Ringworm is most commonly found on the head, neck, shoulders, or saddle/girth area, but can appear anywhere3. It is more typical to see ringworm in young horses or senior horses, as both age groups tend to have less effective immune systems. The good news is that once infected, the horse will develop a natural immunity making it less likely to contract ringworm again in the future.
The fungi responsible for the infection are fairly resistant to environmental factors, including hot and cold temperatures. They can survive for months on fences, stalls, or tack. It can take anywhere from six days to six weeks for symptoms to develop, with a three week incubation period being most common. Ringworm is seen more in winter months, as fuzzy haircoats and increased blanket use is more likely to foster dark, moist areas which are favored by the fungi.
Ringworm is spread by direct and indirect transfers. A direct transfer would be physical contact with an affected animal; it does not have to be a horse. Ringworm can also be found in cattle, dogs, cats, and humans. Indirect transfers occur through the environment. This could happen when a healthy horse rubs against a fence board previously touched by an infected animal. Or, sharing blankets or saddle pads could transmit the spores to a new host.
How to Treat Ringworm
Since ringworm can be transmitted from horses to humans, it’s recommended to wear disposable rubber gloves when handling an affected animal. That said, treating the horse can be accomplished in three steps:
- The first step to treat ringworm is to remove the fungus’ food source, keratin2. Use clippers to remove hair from the bald(ing) spot and add a ½” margin around each lesion.
- Next, at a minimum, wash the affected area with an antifungal antiseptic. If you can, wash the entire horse—this is far more effective at preventing reinfection or additional lesions from developing5. Betadine works well, or you can get a prescription from your vet. Rinse the affected area with diluted white vinegar, then thoroughly dry the horse. Remember, fungi like damp areas—keep the area dry and expose it to sunlight if possible.
- Last, dress the lesion with an antifungal ointment or spray. Equiderma Skin Lotion has reported positive results.
You'll need to disinfect Everything to prevent future outbreaks
However, treating your horse for ringworm isn’t the only action item. As ringworm is highly contagious, you must also disinfect everything—tack, grooming equipment, the clippers you just used, yourself, and any other animals that may have come into contact with the affected horse. This is an example of why separate grooming kits for each horse are a good idea: it’s much easier treat and disinfect one horse and one set of brushes than a whole barn full! Disinfectant should include a fungicide. Virkon is a fungicide that has been successful in decontaminating tack, grooming equipment, blankets, and other items.
It’s important to keep close tabs on your horse’s progress. Check existing lesions; they should be shrinking and growing new hair in the center. Examine your horse’s whole body to ensure there are no additional lesions. If the fungal infection is spreading, or the existing lesions haven’t begun healing within two weeks, it’s time to call your vet for further analysis.
Prevention really is key with ringworm. Good stable management can minimize the risk of contracting ringworm and the spread between animals if an outbreak does occur. One way to prevent possible infection is to disinfect a new stable before moving your horse in. This can be accomplished by spraying down stalls, flooring, buckets, feed troughs, and fences using a sprayable product, preferably one that specifically calls out ringworm. Additionally, new horses should be quarantined to ensure they aren’t carrying any diseases or parasites that could be spread to other horses. A good rule to follow is two to three weeks of quarantine; if no symptoms are present, it should be safe.
The good news about ringworm is that it’s generally more of a cosmetic condition and is easily treatable. Act quickly, monitor progress, and always reach out to your veterinarian with questions.
Kentucky Equine Research https://ker.com/equinews/ringworm-in-horses/
Horse & Rider UK https://ker.com/equinews/ringworm-in-horses/