What is Equine Otohematoma?

What is Equine Otohematoma?

The surgical procedure requires vertical incisions over the concave ear surface so the veterinarian can eliminate the fibrinous clot.

Photo: Courtesy Dr. Rubén Anguiano

By Rubén Anguiano, DVM, MSc, University of Guadalajara, México, WEVA Regional Ambassador


Equine otohematoma—also known as otoserohematoma, hematoma auris, and auricular pseudocyst—is an uncommon ear condition affecting horses of all ages. It is not well-described in medical and surgical equine literature, so many practitioners are unfamiliar with it.

Otohematoma is an accumulation of blood and serous fluid between the conchal cartilage (which makes up the ear) and the perichondrium (connective tissue that envelops the conchal cartilage). It can be caused by blunt or compressive trauma or horse bites, but most of the cases have an idiopathic etiology (unknown cause). Parasites, ticks, and mites can also be involved.

Fluid accumulates when the natural adhesion between the perichondrium, the cartilage, and the skin is damaged by trauma. Clinical signs include severe ear swelling, edema (fluid swelling), erythema (skin reddening), bumps under the skin, pain during palpation, frequent head-shaking and -tilting, and sometimes bloody or purulent (puslike) exudate. The separation between perichondrium and cartilage can cause necrosis (tissue death), chronic inflammation, and ear deformation, so prompt treatment is essential.

If untreated, otohematoma can cause necrosis (tissue death), chronic inflammation, and ear deformation.

Photo: Courtesy Dr. Rubén Anguiano

We recommend a surgical approach to eliminate the blood clot, prevent recurrence, and preserve the ear’s natural position while avoiding drooping or permanent deformation. The surgical procedure requires a vertical incision over the concave ear surface. This allows the veterinarian to eliminate the fibrinous clot via intensive irrigation.

Once the clot is eliminated, the veterinarian will place vertical interrupted sutures over the skin and the underlying cartilage parallel to auricular blood vessels. The sutures can help prevent recurrence and should be removed 10 days after surgery.

During healing, the surgical incision must be cleaned every day and treated with local antiseptics. Systemic antibiotics and anti-inflammatory drugs are recommended for five days.

The veterinarian should also remove any parasites, ticks, or mites for proper healing to occur.

Take-Home Message

Equine otohematoma is a complex, but uncommon, condition. The only effective treatment is surgery, and it should be carried out promptly to avoid chronic ear deformation.

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