Sinus Disease in Donkeys: Respiratory Causes of Nasal Discharge and Facial Swelling

Sinus disease in donkeys means inflammation, infection, or blockage within the air-filled spaces of the skull around the nasal passages. In practice, pet parents often notice nasal discharge first. That discharge may come from one nostril or both, and it may be clear, cloudy, thick, or foul-smelling depending on the cause.

In equids, sinus disease is often divided into primary sinusitis and secondary sinusitis. Primary sinusitis starts in the sinus tissues themselves, often after upper airway inflammation. Secondary sinusitis happens because something else is affecting drainage or invading the sinus, such as dental root infection, trauma, a cyst, fungal disease, or a mass. Secondary causes are especially important because treatment usually needs to address the underlying problem, not only the discharge.

Donkeys can show signs that look similar to horses, but they may be more stoic and hide discomfort. That means mild nasal discharge or subtle facial asymmetry can be easy to miss until the disease is more advanced. Early veterinary evaluation can help your vet sort out whether this is a manageable infection, a dental problem, or a more complex condition.

A donkey’s sinuses can become diseased when normal drainage is blocked or when infection spreads into the sinus cavity. In equids, dental disease is one of the most important causes of secondary sinusitis, especially infection involving the roots of the upper cheek teeth. Because those tooth roots sit close to the maxillary sinus region, infection can drain into the sinus and then out through one nostril.

Other causes include primary bacterial sinusitis after upper respiratory inflammation, facial trauma, foreign material, sinus cysts, progressive ethmoid hematoma, fungal disease, and tumors or other masses. Less commonly, sinus problems can follow procedures or instrumentation involving the nasal passages. In some cases, discharge starts as a respiratory issue but becomes chronic because thick material, damaged tissue, or poor drainage keeps the sinus from clearing.

The pattern of signs can offer clues, but it does not confirm the cause. Foul-smelling one-sided discharge and facial swelling often raise concern for dental involvement. Bloody discharge, obvious distortion of the face, or poor response to routine antibiotics may make your vet more concerned about a cyst, fungal disease, or a mass. That is why a full workup matters before choosing treatment.

Diagnosis starts with a careful history and physical exam. Your vet will look at whether the discharge is one-sided or two-sided, whether it smells bad, whether airflow is reduced, and whether there is pain or swelling over the face. Because dental disease is such a common driver of sinus problems in equids, a sedated oral exam with a speculum and good lighting is often part of the initial plan.

From there, your vet may recommend skull radiographs, endoscopy of the nasal passages, and sometimes sampling of sinus material. Radiographs can help identify fluid lines, tooth root changes, bone involvement, or masses. Endoscopy can help your vet look for discharge coming from a sinus opening, foreign material, bleeding, or obstruction. If the case is chronic, recurrent, or unclear, referral imaging such as CT can provide much more detail than standard radiographs.

Testing is also used to rule out look-alike problems. Nasal discharge can come from the lower airway, pharynx, guttural pouches, teeth, or the sinuses. A routine swab from the nostril is often less useful than a deeper sample because the front of the nose can contain normal contaminants. Once your vet identifies the likely source, treatment can be tailored to the cause and to your donkey’s comfort, handling needs, and overall health.

Not every case can be prevented, but regular dental and head exams can lower the risk of chronic sinus problems. Because upper cheek tooth disease is a common cause of secondary sinusitis in equids, routine oral care matters. Many equids benefit from at least annual dental evaluation, and some younger or older animals need checks more often based on age and findings.

Good prevention also means paying attention to small changes. Early one-sided discharge, bad odor, quidding, feed dropping, or subtle facial asymmetry are worth discussing with your vet before they become a larger problem. Prompt care after facial trauma can also help reduce complications.

Barn management supports respiratory health too. Keep feed and bedding as low-dust as practical, provide good ventilation, and avoid letting chronic nasal discharge go unchecked. If your donkey has had sinus disease before, ask your vet what follow-up schedule makes sense. Some donkeys need repeat dental exams or imaging to make sure the underlying issue has truly resolved.