Equine Epistaxis: What You Need to Know

By Bianca Schwarz, DVM, DrMedVet, Dipl. ECEIM, WEVA board member

Epistaxis—essentially an equine nosebleed—is a common condition that can range from a few drops of blood in one nostril to large volumes of blood draining from both nostrils.

Sources of blood can include the upper and/or lower respiratory tract, the sinuses, and the guttural pouches. But veterinarians typically can’t identify the source of the blood from external examination alone. Thus, a horse will need to undergo further examinations to determine what’s causing the epistaxis. Radiographs, for instance, can help veterinarians visualize blood in the sinuses, which could occur after head trauma (the most common cause of epistaxis). An endoscopic exam of the upper and lower respiratory tract—including guttural pouches—can also help veterinarians identify the cause of bleeding in most cases.

The many causes of epistaxis range from easily treatable to life-threatening conditions. For instance, guttural pouch mycosis—a fungal infection that destroys the blood vessels and nerves—is a potentially fatal cause of epistaxis; veterinarians know that horses with epistaxis caused by repeat guttural pouch mycosis episodes will likely not survive. Bleeding due to foreign bodies or tumors, progressive ethmoid hematomas (slowly expanding masses that originate from the mucous lining of a structure called the ethmoid turbinate, located in the back part of the nasal cavity), or exercise-induced pulmonary hemorrhage can also cause epistaxis. And, in rare cases, epistaxis can be due to the blood’s inability to clot; this is sometimes seen secondary to tumors or immune-mediated diseases and requires specific blood examinations.

The course of treatment for epistaxis depends on the reason behind the bleeding. For instance, a horse with guttural pouch mycosis will need referral to an equine hospital for treatment, which includes surgery to tie off the affected artery. A horse with head trauma and bleeding into the sinuses usually responds best to rest and time and prophylactic treatment with antibiotics to prevent secondary sinusitis. Ethmoid hematomas, on the other hand, will need treatment with laser, formalin injection, or surgery. The key is working with your veterinarian to accurately determine the cause and start the appropriate treatment.

The most important question regarding epistaxis is if the nose bleeding is an emergency. This depends on the volume of blood lost, but also on the cause. As life-threatening diseases can be the cause of epistaxis it is important to have your veterinarian examine horses with nose bleeding thoroughly and promptly.