Cysts, in general, do not normally affect a great deal of horses. One exception may be epidermoid cysts, a type of cyst that is commonly found on the surface of a horse's skin. In some cases they open to the surface of the skin, and in other cases they are contained within the skin. In either case, they are a painful condition for any horse to endure, and most cases require a surgical resolution. Often, they are found around the head of the horse.

Symptoms and Types

• Swelling at the surface of the skin
• Swelling at the bottom of the ear (dentigerous cysts)
• Swelling in the false nostril (atheromas)
• Lesions/cysts filled with keratinaceous debris (protein material found in hair, outer layer of epidermis)
• Grayish, yellowish discharge from the cyst
• Lesion/cyst in the cornea  (eye)

Causes

• Congenital defects
• Abnormalities in the upper layers of the skin

Diagnosis

Your veterinarian will conduct a thorough examination of your horse's skin. In addition to examining the skin, he or she will be able to discern if the lesions are cysts by palpating the area.