Eosinophilic Keratoconjunctivitis in Donkeys
- See your vet promptly if your donkey is squinting, tearing, or has a white or pink raised spot on the eye. Eye disease can worsen quickly.
- Eosinophilic keratoconjunctivitis is an uncommon inflammatory eye condition in equids. It affects the cornea and conjunctiva and can look like an ulcer, plaque, or limbal mass.
- Diagnosis usually requires an eye exam plus corneal or conjunctival cytology to look for eosinophils and rule out infection or a tumor-like lesion.
- Treatment often involves a combination of topical medications, pain control, and close rechecks. Some cases improve faster after superficial keratectomy or plaque removal.
- Healing may take weeks, and recurrence can happen, especially in warm months or in animals with ongoing irritation or hypersensitivity.
What Is Eosinophilic Keratoconjunctivitis in Donkeys?
Eosinophilic keratoconjunctivitis is an inflammatory disease of the cornea and conjunctiva. In equids, it is considered uncommon, but it can be painful and visually dramatic. Affected eyes may develop raised white plaques, pink fleshy tissue near the limbus, discharge, and marked squinting. In published equine reports, the condition is thought to be immune-mediated or hypersensitivity-related rather than a straightforward bacterial infection.
In donkeys, the veterinary literature is limited, but a published case report described a 29-year-old donkey with unilateral discharge and a limbal mass that resolved after topical treatment over about 30 days. Because donkey-specific data are sparse, your vet will usually apply what is known from horses while tailoring care to your donkey’s exam findings, comfort, handling needs, and risk of corneal ulceration.
This condition can resemble other serious eye problems, including corneal ulceration, fungal keratitis, foreign body injury, immune-mediated keratitis, and even tumor-like lesions. That is why a careful eye exam matters. Early treatment can improve comfort, reduce scarring, and help protect vision.
Symptoms of Eosinophilic Keratoconjunctivitis in Donkeys
- Squinting or keeping the eye partly closed
- Excess tearing or mucoid eye discharge
- Raised white, yellow-white, or chalky corneal plaque
- Pink fleshy tissue or a limbal mass at the edge of the cornea
- Red conjunctiva and swollen tissues around the eye
- Cloudiness or surface irregularity of the cornea
- Light sensitivity
- Rubbing the eye or face
Any donkey with squinting, corneal cloudiness, a white plaque, or a new mass-like spot on the eye should be seen by your vet as soon as possible. Eye conditions in equids can change fast, and several emergencies can look similar at first.
Worry more if the eye is suddenly very painful, the cornea looks blue or cloudy, discharge becomes heavy, the donkey will not open the eye, or the lesion seems to enlarge over a day or two. Those signs can overlap with corneal ulceration, stromal abscess, fungal infection, or uveitis.
What Causes Eosinophilic Keratoconjunctivitis in Donkeys?
The exact cause is not fully known. In horses, eosinophilic keratoconjunctivitis is widely considered an immune-mediated condition, and some cases may be linked to hypersensitivity reactions. Seasonality has been reported, with many equine cases appearing during warmer months, which supports the idea that insects, environmental allergens, UV exposure, or surface irritation may play a role.
Other possible contributors include prior corneal trauma, chronic irritation, dry eye, and infectious triggers that either mimic the disease or complicate it. Equine references also note that some cases have been investigated for viral involvement, and your vet may consider herpesvirus or other infectious causes depending on the appearance of the eye and local risk factors.
Because the cornea can react in similar ways to very different problems, the practical answer is that eosinophilic keratoconjunctivitis is often a diagnosis reached after ruling out other causes. That is why your vet may recommend staining the eye, collecting cytology, and sometimes pursuing culture or biopsy if the lesion is unusual or not improving.
How Is Eosinophilic Keratoconjunctivitis in Donkeys Diagnosed?
Diagnosis starts with a full ophthalmic exam. Your vet will usually look for corneal plaques, limbal granulation tissue, conjunctival swelling, discharge, and signs of pain. A fluorescein stain is commonly used to check for corneal ulceration, because treatment choices can change if an ulcer is present.
The most helpful confirmatory test is usually corneal or conjunctival cytology. A sample from the lesion is examined for eosinophils, often with a few mast cells. Finding those cells supports eosinophilic keratoconjunctivitis and helps separate it from some infectious or neoplastic-looking conditions.
Depending on what your vet sees, additional tests may include tear production assessment, evaluation of the lacrimal gland area, culture, biopsy, or referral to an equine ophthalmology service. Referral is especially useful if the eye is not responding, the cornea is deeply involved, vision is threatened, or surgery such as superficial keratectomy is being considered.
Treatment Options for Eosinophilic Keratoconjunctivitis in Donkeys
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Farm-call or clinic eye exam by your vet
- Fluorescein stain and basic ophthalmic assessment
- Corneal or conjunctival cytology when feasible
- Topical broad-spectrum antibiotic if the corneal surface is compromised or infection cannot yet be ruled out
- Pain control such as systemic NSAIDs when appropriate
- Fly control, dust reduction, shade, and a fly mask if tolerated
- Short-interval recheck to confirm the eye is improving
Recommended Standard Treatment
- Complete ophthalmic exam and repeat staining as needed
- Cytology to document eosinophilic inflammation
- Targeted topical anti-inflammatory therapy chosen by your vet based on whether ulceration is present
- Topical antibiotic coverage when indicated
- Atropine if painful spasm or uveitis-like discomfort is present and your vet feels it is appropriate
- Systemic NSAIDs for comfort and inflammation control
- Frequent rechecks over 2-6 weeks, with treatment adjustments based on response
Advanced / Critical Care
- Referral to an equine ophthalmology service
- Sedated detailed eye exam and advanced diagnostics
- Superficial keratectomy, plaque debridement, or other ophthalmic procedure when medical therapy is failing or the lesion is extensive
- Histopathology or biopsy of removed tissue when the lesion is atypical
- More intensive medication plans, including compounded ophthalmic drugs when needed
- Monitoring for secondary infection, deep ulceration, or vision-threatening complications
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Eosinophilic Keratoconjunctivitis in Donkeys
Bring these questions to your vet appointment to get the most out of your visit.
- Does this eye look more like eosinophilic keratoconjunctivitis, an ulcer, fungal keratitis, or another problem?
- Will you stain the eye and collect cytology to confirm what cells are present?
- Is there any sign that vision is at risk right now?
- Which topical medications are safest for this eye based on whether the cornea is ulcerated?
- How often should I expect to medicate the eye, and what handling tips do you recommend for a donkey?
- What changes would mean the treatment plan is not working and we need a recheck sooner?
- Would referral for ophthalmology or superficial keratectomy make sense in this case?
- What management changes at home could reduce recurrence, such as fly control, shade, or dust reduction?
How to Prevent Eosinophilic Keratoconjunctivitis in Donkeys
There is no guaranteed way to prevent eosinophilic keratoconjunctivitis, because the exact cause is still unclear. Still, it is reasonable to reduce surface irritation and allergen exposure as much as possible. Good fly control, cleaner bedding, less dust, and limiting exposure to irritating plant material may help some donkeys, especially during warm seasons when equine cases are reported more often.
Daily observation matters. Catching early tearing, squinting, or a small white plaque can lead to earlier treatment and less corneal damage. If your donkey has had a similar eye problem before, ask your vet whether seasonal monitoring or earlier rechecks during high-risk months make sense.
General eye safety also helps. Check fencing, feeders, hay presentation, and turnout areas for sharp edges or poking hazards. Prompt care for any eye injury, chronic discharge, or rubbing episode may reduce the chance that ongoing irritation will trigger a more serious inflammatory response.