Ethmoid Hematoma in Donkeys: A Cause of Recurrent Nosebleeds

Ethmoid hematoma, more precisely called progressive ethmoid hematoma, is a noncancerous but locally invasive mass that develops from the lining around the ethmoid turbinates in the back of the nasal cavity. Although most published veterinary information comes from horses, donkeys share very similar upper airway anatomy, so your vet will usually approach suspected cases in a comparable way.

These masses are made up of blood, fibrous tissue, and fragile surface lining. They can slowly enlarge over time and may extend into the nasal passages or nearby sinus compartments. That growth is why a donkey may seem fine between episodes, then have repeated nosebleeds over weeks or months.

A key point for pet parents is that this condition is not the same as a simple nose injury. Recurrent bleeding from one nostril, especially without obvious trauma, deserves a veterinary workup. Ethmoid hematomas can look dramatic, but the outlook varies widely depending on size, location, and whether the lesion comes back after treatment.

The exact cause of progressive ethmoid hematoma is still uncertain. Veterinary references describe it as a locally destructive, encapsulated vascular lesion of the nasal passages or paranasal sinuses. In plain language, that means it behaves like an expanding blood-rich mass, but it is not fully understood why it starts.

Researchers have proposed repeated small hemorrhages, abnormal blood vessel changes, and chronic local inflammation as possible contributors. What matters most clinically is that the lesion can continue to enlarge and bleed, even if the original trigger is never identified.

Because the cause is unclear, pet parents should avoid assuming a recurrent nosebleed is due to dry air, dust, or a minor bump. Those factors may irritate the nose, but they do not explain every case. Your vet may also need to rule out other causes of epistaxis, including sinus cysts, infection, dental-related sinus disease, trauma, fungal disease, foreign material, and less commonly neoplasia.

Diagnosis starts with a careful history and physical exam. Your vet will want to know whether the bleeding is one-sided or two-sided, how often it happens, whether there is exercise intolerance or noisy breathing, and whether there has been any trauma, dental disease, or weight loss.

The most useful first-line test is usually upper airway endoscopy. This allows your vet to look inside the nasal passages and see whether there is a characteristic discolored mass near the ethmoid region or blood tracking from that area. In horses, these lesions are often described as greenish-yellow to purple, and that appearance can strongly support the diagnosis.

Imaging is often the next step. Skull radiographs can help identify sinus involvement, but CT is often the most informative option when available because it shows the lesion's size, origin, and extension more clearly. Advanced imaging is especially helpful before treatment planning, since some lesions extend into areas where certain procedures carry more risk.

Your vet may also recommend bloodwork to assess blood loss or look for clotting problems, especially if the bleeding pattern is unusual. In some cases, biopsy is avoided or approached cautiously because these masses can bleed significantly, so diagnosis often relies on the combination of exam findings, endoscopy, and imaging.

There is no proven way to fully prevent progressive ethmoid hematoma, because the underlying cause is not well defined. That can feel frustrating, but it also means pet parents should focus on early detection rather than blame or second-guessing routine management.

The most practical step is to take any repeated nosebleed seriously, even if your donkey seems normal between episodes. Early evaluation may identify a smaller lesion before it causes more obstruction, sinus involvement, or repeated blood loss. Keeping notes on which nostril bleeds, how often it happens, and whether exercise seems to trigger it can help your vet.

Good general donkey care still matters. Regular dental care, prompt attention to nasal discharge or facial swelling, and a clean environment with reasonable dust control can support overall respiratory health and help your vet sort out other causes of epistaxis. These steps do not guarantee prevention, but they can make problems easier to catch and manage sooner.

If your donkey has already been treated for an ethmoid hematoma, follow-up is part of prevention too. Recurrence is common in equids, so scheduled rechecks with your vet are one of the best ways to catch regrowth before signs become severe again.