Dacryocystitis in Horses

Quick Answer
  • Dacryocystitis is inflammation or infection of the tear sac, usually linked to a blocked nasolacrimal duct.
  • Common signs include one-sided tearing, sticky or pus-like discharge, and conjunctivitis that keeps coming back.
  • Many horses improve with a tear duct flush and eye medication, but chronic or structural blockages may need imaging, temporary tubing, or referral.
  • See your vet promptly if your horse has eye pain, squinting, corneal cloudiness, facial swelling, or a draining tract near the inner lower eyelid.
Estimated cost: $250–$3,500

What Is Dacryocystitis in Horses?

Dacryocystitis is inflammation of the tear sac and nearby tear drainage system. In horses, it usually happens when the nasolacrimal duct becomes partially or fully blocked, so tears cannot drain normally from the eye into the nose. Instead, tears spill over the eyelid and may collect bacteria, mucus, and inflammatory debris.

Many pet parents first notice a constantly watery eye on one side of the face. Some horses also develop recurrent conjunctivitis, crusting at the inner corner of the eye, or thicker discharge that keeps returning after basic eye cleaning. The problem may look minor at first, but ongoing blockage can keep irritation going.

This condition is often manageable, especially when your vet can identify and relieve the obstruction early. The outlook is usually good for straightforward cases, but chronic disease, facial trauma, masses, or permanent duct damage can make treatment more involved.

Symptoms of Dacryocystitis in Horses

  • Persistent tearing or overflow of tears from one eye
  • Wet hair or tear staining down the face
  • Mucus, yellow, or pus-like discharge at the inner corner of the eye
  • Conjunctivitis that does not fully improve or keeps coming back
  • Mild swelling near the inner lower eyelid or along the tear duct area
  • Reflux of discharge from the tear openings when the duct is flushed
  • Occasional draining tract or small opening near the medial lower eyelid in chronic cases
  • Facial swelling or discomfort if a deeper obstruction, trauma, or bony change is involved

A watery eye is not always an emergency, but eye problems in horses can worsen quickly. See your vet immediately if your horse is squinting, holding the eye shut, has a cloudy or blue cornea, shows marked swelling, seems painful, or has sudden vision changes. Those signs can point to corneal ulceration, uveitis, trauma, or another eye condition that needs urgent care.

If the main sign is chronic tearing with discharge, your horse still needs a veterinary exam soon. Repeated wiping alone will not fix a blocked tear duct, and ongoing moisture can irritate the skin and allow infection to persist.

What Causes Dacryocystitis in Horses?

In horses, dacryocystitis is most often secondary to obstruction of the tear sac or nasolacrimal duct. Merck notes that blockage may be caused by inflammatory debris, foreign material, or masses pressing on the duct. Once drainage slows or stops, tears back up and the area becomes inflamed or infected.

Other causes can include facial trauma, scarring after previous inflammation, and congenital problems in foals. Young horses may have an abnormal or absent opening at the nasal end of the duct, which can lead to early tearing and chronic conjunctivitis. In some cases, the blockage is not inside the duct itself but comes from pressure outside it.

Less common but important causes include bony changes of the face, such as lacrimomaxillary suture exostosis, which has been reported to obstruct the duct in horses. Because several different problems can look similar from the outside, your vet may recommend more than one test before deciding on the most appropriate treatment plan.

How Is Dacryocystitis in Horses Diagnosed?

Your vet will start with a full eye exam and a close look at the eyelids, conjunctiva, cornea, and inner corner of the eye. This matters because tearing can also happen with corneal ulcers, foreign bodies, uveitis, eyelid problems, or irritation from dust and flies. In some horses, sedation is needed for a safe and complete exam.

A key next step is checking tear duct patency. Your vet may flush the nasolacrimal duct with sterile saline or water to see whether fluid passes normally into the nose, whether there is resistance, or whether mucus and discharge reflux back through the tear openings. If the duct does not open well, that strongly supports obstruction.

For chronic, recurrent, or complicated cases, imaging may be recommended. Skull radiographs with contrast dye placed in the duct can help locate the blockage and look for structural causes. Referral to an equine ophthalmology service may be helpful when your horse has repeated obstruction, facial swelling, suspected trauma, or may need temporary tubing or surgery.

Treatment Options for Dacryocystitis in Horses

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Budget-Conscious Care

$250–$600
Best for: Mild to moderate first-time cases with tearing and discharge but no severe pain, corneal ulcer, facial swelling, or suspected trauma.
  • Farm call or clinic exam
  • Basic eye exam to rule out more urgent eye disease
  • Nasolacrimal duct flush
  • Topical ophthalmic medication if your vet finds infection or conjunctivitis
  • Short recheck if signs are improving
Expected outcome: Often good if the blockage is soft debris or mild inflammation and the duct can be reopened.
Consider: Lower upfront cost, but recurrence is possible if the underlying cause is structural, chronic, or outside the duct. Some horses need repeat flushing or escalation.
Most Common

Recommended Standard Treatment

$600–$1,500
Best for: Most horses with persistent, recurrent, or treatment-resistant tearing and discharge.
  • Complete ophthalmic exam, often with sedation
  • Nasolacrimal flushing and repeat lavage as needed
  • Fluorescein stain or other ocular surface testing when indicated
  • Topical antimicrobials and anti-inflammatory treatment chosen by your vet
  • Skull radiographs, with or without contrast study, for recurrent or long-standing obstruction
  • Follow-up visits to confirm drainage has improved
Expected outcome: Good to fair, depending on whether the obstruction can be cleared and whether there is chronic scarring or an external compressive cause.
Consider: More diagnostics improve decision-making, but cost range is higher and some horses still need referral or a procedure to maintain duct patency.

Advanced / Critical Care

$1,500–$3,500
Best for: Chronic obstruction, congenital abnormalities, permanent duct damage, facial swelling, suspected mass effect, or cases that fail field treatment.
  • Referral to an equine ophthalmologist or hospital service
  • Advanced imaging or contrast dacryocystorhinography
  • Temporary catheter or tubing placement to keep the duct open during healing
  • Hospital-based treatment and repeated flushing
  • Surgical creation of a new drainage pathway or correction of an underlying structural problem when needed
  • Management of associated facial trauma, masses, or chronic bony obstruction
Expected outcome: Fair to good when the underlying cause can be corrected, though chronic structural disease may require longer treatment and closer follow-up.
Consider: Most comprehensive option, but it involves referral logistics, higher cost range, and sometimes hospitalization or repeat procedures.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Dacryocystitis in Horses

Bring these questions to your vet appointment to get the most out of your visit.

  1. You can ask your vet whether this looks like a blocked tear duct, conjunctivitis, a corneal problem, or another eye condition.
  2. You can ask your vet if a nasolacrimal flush is appropriate today and what they learned from the flush.
  3. You can ask your vet whether my horse needs fluorescein stain, sedation, or a more complete ophthalmic exam.
  4. You can ask your vet what might be causing the blockage in this specific horse, such as debris, trauma, congenital narrowing, or facial bone changes.
  5. You can ask your vet when skull radiographs or contrast imaging would be the next step.
  6. You can ask your vet what signs mean this has become urgent, including squinting, cloudiness, swelling, or worsening discharge.
  7. You can ask your vet how likely recurrence is and what follow-up schedule they recommend.
  8. You can ask your vet for the cost range of conservative, standard, and referral-based care before we decide on the next step.

How to Prevent Dacryocystitis in Horses

Not every case can be prevented, especially when a horse has congenital narrowing, facial trauma, or a structural blockage. Still, good eye care can lower the chance that mild irritation turns into a bigger drainage problem. Check your horse's eyes regularly for tearing, discharge, swelling, or rubbing, and have recurring signs examined instead of repeatedly wiping them away and waiting.

Reduce avoidable irritation where you can. Dust control in stalls and arenas, sensible fly management, and prompt treatment of conjunctivitis or eyelid irritation may help limit inflammation around the tear drainage system. If your horse has had facial injury or swelling near the eye or nose, ask your vet whether follow-up is needed even if the eye looks mostly normal.

Foals with chronic tearing should be evaluated early because congenital blockage at the nasal end of the duct is a recognized cause of epiphora in young horses. Early treatment often gives the best chance of restoring normal drainage before long-term inflammation and scarring develop.

Find a Vet Near You