Ringworm in Horses (Dermatophytosis)

Updated July 6, 2024 | By: Dr. Lydia Gray

Ringworm is not a parasite but a fungal infection of the skin and hair. Also known as dermatophytosis, this skin disease is primarily caused by the fungus Trichophyton equinum or Trichopyton mentagrophytes found in the environment.

What Does Ringworm in Horses Look Like?

The condition may start out looking like hives, then develop into the more typical scaly, crusty, round areas of hair loss. Ringworm is not usually itchy or painful, but it can be. It is most common in areas where the skin and hair are broken or damaged, such as under the saddle and girth or on the face and neck.

The fungal infection seems to occur more often in the fall and winter when horses are kept indoors closer together and away from fresh air and sunlight.

Horses with weak immune systems are most at risk for contracting ringworm. This includes the very young and the very old, horses receiving poor nutrition or certain medications, and horses that are debilitated or currently suffering from another disease.

How to Treat Ringworm in Horses

While ringworm usually goes away on its own, treating the horse and disinfecting the environment help shorten the recovery period, decrease the severity of the condition, and reduce spread to other horses.

A veterinarian should be involved in both diagnosing and planning a treatment strategy, which may include:

• quarantine
• daily bathing
• sanitizing equipment, stalls and other things the infected horse may have come in contact with

Diluted solutions of chlorhexidine, povidone iodine, lime sulfur, and bleach are commonly used to destroy the organism both on the horse and in the environment.