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Also Known As

Circular itchy lesions


Ringworm is a highly contagious zoonotic fungal disease that can infect humans, dogs and cats, as well as horses. It is caused by the fungal species Trichophyton equinum. Though not considered a serious disease, it can spread throughout the stable or herd, affect staff and owners, and prevent the normal use of the horse.

Ringworm develops in a circular pattern with patches of raised hair. The hair gives way easily if rubbed or plucked, and hair loss follows, leaving a scaling of the underlying skin. Small pustules often develop.

Initially lesions are itchy and remain sensitive to touch for long periods. Lesions are most common on the head, but can occur on the legs, feet, body or tail area.

Sometimes the fungus does not develop in a circular pattern and the skin condition may resemble an auto-immune disease. The disease often resolves spontaneously, but fungal spores in the contaminated stable and equipment may persist for years.


  • Patches of raised hair forming a circular pattern
  • Hair loss
  • Scaling of underlying skin creating lesions


Ringworm is usually caused by the fungal species Trichophyton equinum, although it may also be caused by Microsporoum species and several other fungi. In any case, it is highly contagious and can be passed to humans, dogs and cats, as well as other horses.


Once infected, no treatment shortens the healing time of ringworm, therefore, prevention is the key to avoiding this highly contagious condition.

Results of vaccinations are variable and repeated boosters are needed for maximum effectiveness.

Hygienic practices are the key, since they minimize the chance of environmental contamination. Periodic disinfection of the stable environment and all equipment can kill any spores that contaminate the premises.

In addition, prompt treatment of any cases will keep the disease from spreading to other horses.

A local veterinarian can give the best advice concerning the fungal species involved and the best disinfectants to use in controlling the fungi.


Treatment of ringworm includes clipping away the infected hair at the margins of the ringworm patch and bathing the skin lesions with Betadine soap to remove the dead scales.

Gloves should be worn during treatments and all grooming materials thoroughly disinfected after use. Oral treatment is also available, but results vary and it does not quickly reduce the spread of the disease.

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EquiMed Staff

EquiMed staff writers team up to provide articles that require periodic updates based on evolving methods of equine healthcare. Compendia articles, core healthcare topics and more are written and updated as a group effort. Our review process includes an important veterinarian review, helping to assure the content is consistent with the latest understanding from a medical professional.