From: Equestrian and Horse | Horse Ailments
Ringworm
This is a fungal infection that causes small round patches to form on the skin surface. Ringworm is also known as Tinea.
Symptoms
Causes
Ringworm is caused by a Fungal infection which affects the skin of the horse, these fungi are called dermatophytes. Ringworm can be easily passed on from one horse to another through direct contact or through contact via rugs, stables and fencing etc.
Treatment