Overview of Canine Epiphora (Excessive Tearing)
Epiphora is an abnormal overflow of tears down the face that results from either obstruction of tear drainage through the nasolacrimal (tear duct) system or overproduction of tears that overwhelms the normal drainage system. The overproduction of tears is most often a reflex, activated to expel irritating material from the surface of the eye or when significant irritation develops inside the eye. Although uncommon in dogs, epiphora may also result from overactive lacrimal (tear) glands and be unassociated with any source of irritation.
Normal dogs may occasionally have minor tear overflow or minor eye discharge. However, excessive, chronic or recurrent bouts of epiphora suggest a problem may be present.
Tears are continuously produced on the eye in most animals. With each blink of the eyelids, tears are pushed along the outer aspect of the eyelids towards the nose. A small hole called a puncta is present in both the upper and lower eyelid very close to the where the lids meet near the nose. Tears normally flow down these two drainage holes into a central collecting sac (lacrimal sac) that sits just under the skin below the eye. From this sac, a small tube or duct (nasolacrimal duct) carries the tears into the nose. In some animals the duct opens just inside the nostril. In other animals, the duct opens further back in the nose. The tears also help keep the nose and nostril moist.
While tears are typically colorless, they can dry to a dark red-brown-black crust. Chronic tearing can result in a brown to rust-colored staining of the hair around the eyes and face of animals. This is believed to be due to porphyrins or other pigment-like substances present in the tears. These same substances may also be present in saliva and cause similar staining of the hair when the dog chronic licks are certain area.
Tears that spill over onto the face can also be irritating to the skin of the face. Moisture and bacterial build-up in that area aggravates this irritation.
Causes of Tearing in Dogs
Epiphora can be caused by numerous conditions. Some common causes of tear flow obstruction include:
Epiphora can also result when tear production increases due to irritation of the eye or stimulation of the tear glands. Common causes of epiphora in this group include:
Some of the above disorders cause both obstruction of tear flow and excessive tearing.
What to Watch For
Diagnosis of Epiphora in Dogs
Veterinary care often includes diagnostic tests to determine what is causing the epiphora or ocular discharge. Epiphora is initially classified into one of three categories:
Once a specific diagnosis has been established, appropriate treatment can be instituted.
There are several potential diagnostic tests. Your cat may be referred to a veterinary ophthalmologist for further evaluation and completion of some of these tests, which may include:
Treatment of Epiphora in Dogs
The goals of treating epiphora include 1) eliminating any causes of excessive tearing, 2) eliminating any obstruction to tear flow (if possible), 3) decreasing the irritation caused by the tears themselves, and 4) keeping the face and area around the eye dry and clean. Specific treatment depends on the cause of the epiphora or ocular discharge. There is no general nonspecific treatment for epiphora.
Treatment of Eye and Orbital Disorders
Management of Chronic Epiphora
Recommendations for home care depend upon the underlying cause of the problem. In addition, some general care is necessary to maintain the health of the eye.
Gently clean away any eye discharge with a sanitary cloth or tissue, and keep the area clean and dry until the cause of the problem is identified.
Do not delay in bringing your pet to a veterinarian for examination as some causes of epiphora, especially those sudden in onset, are potentially vision threatening and require immediate medical or surgical attention.