Epistaxis is a common condition in horses that refers to bleeding from the nostrils. Nosebleeds can range in severity and may result from trauma, underlying health conditions or exercise. [1]

The majority of nosebleeds in horses are caused by minor trauma or irritation and resolve within 10 to 15 minutes. However, recurrent nosebleeds or severe bleeding can indicate an underlying condition that requires veterinary attention.

Treatment of epistaxis in horses largely depends on the identified cause of the bleeding. Horses may need rest, medication, or other interventions to diagnose and address the bleeding.

To minimize nosebleeds in your horse, it is important to maintain a clean and well-ventilated barn environment and manage dust and exposure to respiratory irritants. Training and exercise should be increased gradually, and stalls and turnout areas should be checked regularly for objects that could cause injury. [2]

While it can be alarming to see blood in your horse’s nostrils, understanding the causes of this condition and knowing how to respond is essential for horse owners and caregivers.

Epistaxis (Nosebleed) in Horses

A one-off nosebleed in your horse might not be a significant concern, but some horses experience recurrent or prolonged nosebleeds that need to be evaluated by a veterinarian.

The most obvious sign of a nosebleed is the presence of blood in one or both nostrils. Depending on its origin, this could manifest as a few droplets, a light stream, or a more substantial amount of blood. [3] Bright red or dark blood indicates a fresh wound, while blood that is brown or black signifies an older hemorrhage.

Some horses, particularly racehorses, may have recurrent nosebleeds linked to intense physical activity due to Exercise-Induced Pulmonary Hemorrhage (EIPH). In such cases, blood is observed dripping from the nostrils after strenuous exercise.

If recurrent bleeding episodes are not connected to exercise or are accompanied by other symptoms, this could be a sign of an underlying condition. Other conditions that can cause epistaxis in horses include bleeding disorders, respiratory issues, infections, tumors or major traumas. [1]

Clinical Signs

Other clinical signs that may accompany recurrent or severe nosebleeds in horses include;

  • Headshaking and rubbing of the nose
  • Coughing
  • Poor performance
  • Lethargy
  • Anxiety
  • Difficulty breathing

Causes of Nosebleeds in Horses

Some causes of nosebleeds are minor and self-resolving, but others can indicate a more serious underlying condition. Common causes of epistaxis in horses include:

  1. Exercise-Induced Pulmonary Hemorrhage: Often seen in racehorses, and other speed event horses, after intense exercise
  2. Trauma: Injuries to the head or nasal passages
  3. Foreign Bodies: Objects lodged in the nostril that cause tissue damage [1]
  4. Sinus Irritation or Infection: Inflammation in the sinuses making blood vessels susceptible to rupture [1]
  5. Allergies: Resulting in nasal irritation and bleeding [1]
  6. Respiratory Infections: Leading to nasal inflammation and bleeding
  7. Tumors: Growths in the nasal passages or sinuses
  8. Bleeding Disorders: Conditions affecting blood clotting
  9. Fungal Infections: Such as Aspergillosis, resulting in guttural pouch mycosis
  10. Prolonged Use of NSAIDs: Leading to bleeding issues
  11. Environmental Factors: Dry or cold air irritation

Exercise-Induced Pulmonary Hemorrhage (EIPH)

One of the most common causes of nosebleeds in athletic horses is exercise-induced pulmonary hemorrhage (EIPH). This condition occurs frequently in racehorses and can severely impact athletic performance if it is left untreated. [4]

An estimated 55 – 90% of Thoroughbred racehorses in training are affected by EIPH to some degree. Horses with EIPH are sometimes referred to as “bleeders.” [4][5]

EIPH is a condition in which intense exertion causes the tiny blood vessels in a horse’s lungs to burst. This leads to blood accumulating within the lungs and air passages, sometimes causing bleeding from the nostrils. EIPH can also arise as a secondary issue, stemming from other problems such as infections or equine asthma.

After a bout of strenuous exercise, affected horses may show following signs of EIPH: [5][6]

  • Nosebleed (mild to severe)
  • Excessive swallowing
  • Coughing
  • Dyspnea (labored breathing)

Only 5% of horses affected by EIPH experience nosebleeds. In most cases, bleeding occurs in the lungs with no external bleeding from the nose. [7]


EIPH is typically diagnosed through endoscopic examination of the trachea and lungs. The endoscope is a small camera that is inserted into the nose and down the trachea to check for the presence of bleeding. This procedure is conducted 30 to 90 minutes after exercise. [5][8]

Bronchoalveolar lavage is another diagnostic test that involves flushing the horse’s lungs with a small amount of fluid to detect blood in the airways. This method has fewer limitations than endoscopy and can help diagnose horses with minimal symptoms. [9]


Treatment for EIPH involves a combination of rest, reduced exercise intensity, anti-inflammatory medications, and supplements. A diuretic medication called Lasix (furosemide) may be administered to reduce blood pressure and decrease hemorrhaging in the lungs. [10]

While Lasix is very effective for treating EIPH, there are alternative treatments available, including Concentrated Equine Serum (CES) and nasal strips. Discuss treatment options for horses with EIPH with your veterinarian.


Horses can develop nosebleeds following an acute injury to the head or nose. Force applied to the nose can cause blood vessels in the nostrils to rupture, resulting in short-term bleeding. These injuries are often minor, and bleeding typically ceases within 15 minutes. [3]

Bleeding caused by medical or veterinary procedures is called iatrogenic trauma. Medical procedures such as nasogastric intubation or endoscopy can result in nosebleeds bleeding from trauma to the horse’s delicate nasal tissues. [1]

Guttural Pouch Mycosis (GPM)

Guttural pouch mycosis (GPM) is a serious and rare condition caused by the presence of fungal organisms in the horse’s guttural pouches. These pouches are air-filled structures located in the horse’s head, adjacent to the Eustachian tubes. [11]

When the horse inhales Aspergillus fungal spores from their environment, they invade and colonize the walls of arterial blood vessels in the horse’s guttural pouch. The resulting mycotic plaque deteriorates the vessel walls, leading to spontaneous nosebleeds. [12]

Horses suffering from GPM often exhibit bleeding or discharge from one or both nostrils even when they are at rest. Typically, these horses experience a significant nosebleed event, which is then followed by several weeks of minor bleeding episodes. Subsequently, another major bleeding event may occur, which can be life-threatening.

Since the guttural pouches are situated near important cranial nerves, GPM is often associated with cranial nerve dysfunction. Other symptoms include noisy breathing (gargling), difficulty swallowing and headshaking. [13]


To diagnose a horse with GPM, veterinarians utilize respiratory endoscopy. This nasal endoscopy technique provides a detailed view of the nasal passages and guttural pouches, offering invaluable insights for clinicians. [12][13]

Your veterinarian will use a small flexible endoscope, inserting it through the nostrils to reach the guttural pouches. This allows for a thorough examination of the pouches’ lining, enabling the identification of mycotic plaques, blood clots, and the evaluation of inflammation.


Early detection of GPM offers a generally favorable prognosis for horses.

Treatment of guttural pouch mycosis involves flushing the guttural pouches and administering antifungal medication. As long as the mycotic plaque is active in the guttural pouches, there remains a risk of sudden hemorrhage. [11][13]

Successful treatment of GPM can take many months, often requiring prolonged antifungal treatments to effectively eliminate the fungus. Surgery may be required to tie up (ligate) the affected carotid artery and stop persistent hemorrhaging, but this procedure is difficult and poses a risk of further bleeding. [12]

Progressive Ethmoidal Hematoma (PEH)

Progressive ethmoidal hematomas (PEH) are benign (non-cancerous) masses that can develop in the horse’s paranasal sinuses and nasal passages.

The ethmoid labyrinth is a complex system of interconnected air-filled cavities located within the skull, specifically in the region between the eyes and extending into the nasal passages.

These structures are part of the horse’s respiratory system and play important roles in air filtration, humidification, and the overall function of the nasal passages. [14]

The exact cause of ethmoidal hematomas remains unclear, but they are believed to arise from infection, inflammation, or injury to the delicate blood vessels in the ethmoid labyrinth, leading to recurrent bleeding. [15]

Frequent bleeding thickens and stretches the submucosa, forming a capsule or mass. As the bleeding episodes continue, the mass grows larger and can damage the surrounding bone and soft tissue. [16]

Clinical signs of PEH vary depending on the size and location of the hematoma, as well as the extent of its impact on surrounding structures. Some common signs include:

  • Spontaneous nosebleeds (typically unilateral or from one nostril)
  • Obstructed sinus drainage and nasal discharge
  • Dyspnea (obstructed airflow) and respiratory noise
  • Dysphagia (difficulty swallowing)
  • Facial swelling
  • Halitosis (bad breath)


To diagnose PEH, a combination of clinical examination, endoscopy, and advanced imaging methods is utilized. PEH can often resemble other respiratory issues, requiring a differential diagnosis. [16]

Your veterinarian will examine the internal structures of the nose by inserting the endoscope through one nostril into the nasal passage. Both nasal passages should be examined, as PEHs usually appear on just one side. This examination might cause minor bleeding.

The appearance of hematomas can vary, manifesting in shades of green, yellow, red, or purple. These masses can obstruct the nasal cavity. Sometimes, they are discovered accidentally during endoscopic evaluations for unrelated health concerns. [14]

Other diagnostic techniques, such as radiography, magnetic resonance imaging (MRI) or computed tomography (CT) may be used to determine which structures are affected and analyze the extent of any damage. [16]


Surgical removal is the most common treatment for PEH, particularly for larger or more complex hematomas. Typically, the horse is placed under general anesthesia, and a procedure known as a bone flap is performed. This involves temporarily removing a section of the skull to access the underlying structures. [16]

A frontonasal bone flap provides the veterinarian with access to the nasal portion of the ethmoidal labyrinth to remove the hematoma. [14] Because the ethmoidal labyrinth is extremely complex, this is a challenging surgery.

If left untreated, PEH can reduce the horse’s athletic performance and may become life-threatening, especially if the hematoma grows to obstruct the airway. [16]

Coagulation (Blood Clotting) Disorders

A coagulation disorder is a condition in which the horse’s blood does not clot normally. Horses with coagulation disorders are more prone to spontaneous bleeding, including nosebleeds. [17]

Clotting is a crucial process that helps prevent excessive blood loss when a blood vessel is injured. The formation of blood clots requires a complex interaction of clotting factors, and a malfunction in these factors can result in excessive bleeding.

Coagulation disorders are either congenital or acquired. Congenital conditions are present from birth and usually have a genetic basis, while acquired disorders develop later in life and often as secondary effects due to conditions such as liver disease or toxin exposure.

Several coagulation disorders are linked to epistaxis in horses, including:

  • Thrombocytopenia (low platelet count)
  • Von Willebrand’s Disease
  • Hemophilia
  • Acquired clotting disorders (e.g. disseminated intravascular coagulation)

The diagnosis and treatment of horses with coagulation disorder depends on the specific condition. If you suspect your horse has a bleeding disorder, contact your veterinarian for examination.


Neoplasia refers to the abnormal and uncontrolled growth of cells, leading to the formation of benign (non-cancerous) or malignant (cancerous) tumors in the horse’s airways.

Horses with neoplasia in the sinuses or nasal passages may exhibit clinical signs including nosebleeds, nasal discharge and labored breathing. [1]

Neoplasms associated with nosebleeds in horses include:

  • Squamous Cell Carcinoma (SCC): This type of skin cancer can develop in the nasal passages and is one of the more common neoplasms to cause nosebleeds.
  • Ethmoid Hematomas: While not malignant, these masses can cause recurrent episodes of epistaxis.
  • Other Tumors: Though less common, other tumors, both benign and malignant, can develop in the nasal passages or sinuses and lead to nosebleeds.


If neoplasia is suspected as a cause for recurrent nosebleeds, your veterinarian may request diagnostic imaging such as X-rays or CT scans, to ascertain the size, location, and extent of the tumor.

Your veterinarian may also perform an endoscopy, which involves inserting a flexible camera into the nasal passages to visualize any masses or obstructions.

If a mass is identified during this procedure, a biopsy is performed, where a tissue sample is taken to determine the type of neoplasia.


The treatment approach largely depends on the type and location of the tumor. Some tumors can be surgically removed, either through the nostrils or by making an incision into the sinuses.

In the case of malignant tumors, radiation or chemotherapy may be considered.

Nasal Amyloidosis

Nasal amyloidosis is a relatively rare condition in horses that can result in nosebleeds. It involves the deposition of an abnormal protein called amyloid in the tissues, specifically within the nasal passages of the affected animal.

In addition to epistaxis, nasal amyloidosis can cause inflammation, chronic nasal discharge, and obstruction if masses form in the nasal passages. [1][18]


Diagnosis is typically made through biopsy of the nasal tissue, followed by histopathological examination which confirms the presence of amyloid protein.


There’s no specific cure for nasal amyloidosis. Treatment is often supportive and may include surgical removal of large amyloid deposits if they obstruct the nasal passages.

It’s also important to address any underlying inflammatory conditions that might be contributing to the development of the disease.

First Aid for Horse Nosebleeds

If you notice your horse has a nosebleed (epistaxis), it’s essential to remain calm and take immediate steps to ensure the safety and well-being of your horse. [3]

Contact your veterinarian if the bleeding persists from the nose for more than 15 minutes. Keep the horse as still as possible to try and slow the bleeding. [3]

Here are some first aid steps to follow:

  1. Stay Calm and Keep the Horse Calm: Your horse may be startled or anxious. Speak to them in a soothing voice and avoid sudden movements. If your horse is in an environment that could be causing stress, consider moving to a quieter location.
  2. Do Not Insert Anything into the Nostril: Do not put anything in your horse’s nose to stop a nosebleed, as this can exacerbate the bleeding or push foreign objects further up. Horses are obligatory nasal breathers, which means they cannot breathe through their mouths and need their nasal passages to be clear for respiration. [2]
  3. Check the Horse’s Vital Signs: Monitor the horse’s heart rate, respiratory rate, and temperature. This can give you an indication of the severity of the situation and can be useful information for your veterinarian.
  4. Apply Cold Compress: If the source of the bleeding is external (e.g., from trauma), you can apply a cold compress, ice pack or wash cloth to the area to help reduce bleeding and swelling.
  5. Limit Movement: Stop exercising your horse and try to keep them as still as possible. If your horse is experiencing a severe nosebleed due to exertion, it’s crucial they rest to support recovery.
  6. Notify your Veterinarian: Even if the nosebleed appears to stop on its own, it’s recommended to get in touch with your veterinarian. They can help determine the cause and advise if further treatment or observation is needed.
  7. Document the Episode: Make a note of when the nosebleed occurred, its duration, and any potential causes (e.g. a recent strenuous workout). This can be beneficial information for your veterinarian and for monitoring any future incidents.
  8. Monitor for Other Symptoms: Watch for other signs like coughing, difficulty breathing, or swelling. These can be indications of more severe underlying issues.

Nosebleed Prevention

Preventing nosebleeds in horses involves a combination of proper care, monitoring, and understanding potential triggers. Many causes of epistaxis in horses are influenced by environmental factors and management practices.

Follow these steps to reduce your horse’s risk of nosebleeds:

  1. Veterinary Check-ups: Regular veterinary examinations can help identify and address underlying health issues that might predispose a horse to nosebleed.
  2. Gradual Training: For athletic horses, ensure an appropriate training regimen and slowly increase exercise intensity to reduce the risk of conditions such as EIPH.
  3. Safe Environment: Keep stables, pastures and turnout areas free from sharp objects and potential hazards to minimize the risk of trauma.
  4. Optimal Humidity: Maintain a stable environment with appropriate humidity to prevent nasal passage dryness, which can make nostrils more susceptible to bleeding.
  5. Air Quality: Reduce dust in your horse’s environment, which can contribute to inflammation in the respiratory tract. Materials such as hay, straw, manure, shavings and animal dander are common sources of barn dust. [2]
  6. Proper Ventilation: Poor ventilation in your horse’s stable can lead to ammonia build-up in the air, which contributes to airway inflammation.
  7. Clean Feed: Ensure that hay or feed is free from debris, mold or dust, which can irritate the nasal passages.
  8. Avoid Overuse of Medications: Some drugs, such as NSAIDs, can increase the risk of bleeding if used excessively. Follow dosage guidelines closely.
  9. Manage Respiratory Health: Address respiratory infections, allergies, or conditions such as equine asthma promptly. Follow your veterinarian’s treatment recommendations
  10. Monitor Seasonal Changes: Certain grasses or seasonal allergens can irritate a horse’s nasal passages. If your horse has nosebleeds at specific times of the year, it might be due to a seasonal allergy.

While many preventive measures can be taken to reduce the risk of nosebleeds in horses, not all nosebleeds are preventable. Factors such as genetic predisposition, unforeseen trauma, or the sudden onset of a medical condition can result in bleeding from the nose.

Therefore, although diligent care can significantly minimize the risk, horse owners must remain vigilant and seek veterinary advice when nosebleeds occur.


Epistaxis, or nosebleeds, in horses can be concerning, but with prompt attention and appropriate care, many horses recover without complications.

Whether the nosebleed results from a minor injury or is linked to conditions like EIPH, you can implement preventative measures to reduce the risk of future episodes.

Consult with your veterinarian to address your concerns about nosebleeds in your horse, especially if bleeding is recurrent or accompanied by other symptoms.

Is Your Horse's Diet Missing Anything?

Identify gaps in your horse's nutrition program to optimize their well-being.


  1. Archer, D. Differential Diagnosis of Epistaxis in the Horse. In Pract. 2008.
  2. Mazan, M. Equine Exercise Physiology—Challenges to the Respiratory System. Anim. Front. Rev. Mag. Anim. Agric. 2022.
  3. Morgan, R. et al.Epistaxis – nosebleed for horses. Vetlexicon Equis. Accessed Aug. 10, 2023.
  4. Bayly, W.Exercise-Induced Pulmonary Hemorrhage—An Occupational Hazard of High-Speed ExerciseAmerican Association of Equine Practitioners (AAEP). 2021.
  5. Brown, C. et al.Lung: EIPH (exercise-induced pulmonary hemorrhage) in horses. Vetlexicon Equis from Vetlexicon – Definitive Veterinary Intelligence. Accessed Aug. 11, 2023.
  6. Birks E.K. et al.Exercise-Induced Pulmonary Hemorrhage. Vet. Clin. North Am. Equine Pract. 2003.
  7. Lascola, K.Exercise-Induced Pulmonary Hemorrhage in Horses – Respiratory System. Merck Veterinary Manual. Accessed Aug. 11, 2023.
  8. Doucet M.Y. and Viel L.Clinical, Radiographic, Endoscopic, Bronchoalveolar Lavage and Lung Biopsy Findings in Horses with Exercise-Induced Pulmonary Hemorrhage. Can. Vet. J. 2002.
  9. Meyer T.S. et al. Library Quantification of Exercise-Induced Pulmonary Haemorrhage with Bronchoalveolar Lavage. Equine Vet. J. 1998.
  10. Erickson H.H. et al. Review of Alternative Therapies for EIPH. American Association of Equine Practitioners (AAEP). 2007
  11. Dobesova O. et al. Guttural Pouch Mycosis in Horses: A Retrospective Study of 28 Cases. Vet. Rec. 2012.
  12. Barakzai S. et al.Guttural pouch: mycosis in horses. Vetlexicon Equis from Vetlexicon – Definitive Veterinary Intelligence. Accessed Aug. 13, 2023.
  13. Alderman L.Guttural Pouch Infections. American Association of Equine Practitioners (AAEP). Accessed Aug. 06, 2023.
  14. Stich K.L. et al. Progressive Ethmoid Hematoma in Horses.Compendium on Continuing Education for the Practicing Veterinarian – North American Edition. 2001.
  15. Hawkins J.F., Chapter 15 – Lasers in Veterinary Surgery. In: Equine Surgery (Fifth Edition). 2019.
  16. Colahan P. et al.Ethmoid: hematoma in horses. Vetlexicon Equis from Vetlexicon – Definitive Veterinary Intelligence. Accessed Aug. 06, 2023.
  17. Cotter S.Bleeding Disorders of Horses – Horse Owners. Merck Veterinary Manual. Accessed Aug. 10, 2023.
  18. Østevik L. et al. Nasal and Ocular Amyloidosis in a 15-Year-Old Horse. Acta Vet. Scand. 2014.