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Ringworm in HorsesBy Kentucky Equine Research Staff · December 21, 2011

Ringworm is a common term used to describe scaly or crusty patches of skin where the horse’s hair is coming out. Caused by a fungus, ringworm can be passed from horse to horse and also from horses to humans. Spores can be spread on grooming tools, tack, or blankets, or may be picked up from the environment. Horses can get ringworm at any season of the year, but winter, with its fuzzy-coated horses and frequent use of blankets, is a common time for ringworm to show up.

The term seems to suggest that the lesions have a circular pattern (not true in every case) and that the malady is caused by a worm (not true in any case). Lesions may or may not be itchy. Several types of fungus are responsible for ringworm, and the particular organism may cause slight local swelling or hives as well as patchy hair loss.

Treatment begins with a culture of a skin scraping or hair sample to identify the fungus and rule out other conditions with similar signs. After a diagnosis is made, a veterinarian may prescribe a whole-body wash with a fungicide. This is far more effective than simply treating the visible lesions. Owners should wear rubber gloves when handling or bathing a horse with ringworm, as the fungus is not host-specific. A second fungicide bath a week after the first treatment may be necessary in some cases.

In an otherwise healthy horse, ringworm will usually subside in a few months even without treatment. For the horse’s comfort and to prevent the spread of the infection to other animals (dogs and cats are also susceptible), treatment is recommended.