Crusty Eye Mucus in Dogs

By Valerie A. Modreski

A certain amount of crusty eye discharge is expected for dogs, but excessive amounts or changes in secretion color and texture can indicate a clinical condition. Watching for changes in your dog's ocular discharge, and knowing what to look for, can save your dog from discomfort or a more serious condition.

Canine Epiphora

A crusty mucous discharge from your dog's eyes may be serious, and your veterinarian should be consulted. The clinical term epiphora means an over-abundance of tear production. Normally, this overflow is redirected internally and drains down the back of your dog's throat. This process becomes interrupted when the lacrimal duct is blocked and the excess flows beneath your dog's eyes causing a crusty build up.

Symptoms of epiphora include red staining on the fur below your dog's eyes, consistent dampness that can lead to bacterial infection, mild odor and skin irritation. While epiphora is typically not serious, treatment may include a surgical procedure in which your veterinarian will flush the lacrimal duct blockage and enlarge the opening.

Dry Eye

Your dog's natural tear production is a bodily function designed to lubricate the eye orb and flush away potentially damaging foreign matter. Keratoconjunctivitis sicca, or dry eye, can be caused by tear duct trauma, nerve damage, drug interaction, an adverse reaction of the immune system or repetitive eye infections. A thick yellowish crusty discharge can be indicative of canine dry eye.

To test for dry eye, your veterinarian will use a Schirmer tear test strip. This absorbent strip is placed over the eye orb for roughly one minute. The results are compared to normal values of tear production, and if your dog's tear production levels are low, he may be diagnosed with dry eye.

Treatment is recommended to avoid chronic eye infections, cornea irritation and, eventually, permanent scarring. Treatment and management therapies include cyclosporine ophthalmic drops or ointment, a tacrolimus solution and artificial tears. In severe cases your veterinarian may recommend surgery.

Canine Conjunctivitis

Canine conjunctivitis may cause a crusty ocular discharge. The moist tissue layer that lines your dog's eyelids, and coats the front of the eye, is called the conjunctiva. When this protective layer becomes inflamed, the condition is called conjunctivitis, or pink eye.

Squinting, chronic blinking, redness and mucous discharge are symptoms for canine conjunctivitis. Your veterinarian will conduct an eye exam using a fluorescein stain to identify foreign material, scratched dead tissue, ulcers, scarring and pus.

Treatment is based on the originating condition which can include tumorous cancer, bacterial infection, chronic food or atmospheric allergies and tear duct obstruction.

Canine Glaucoma

Canine glaucoma is a serious condition requiring veterinary care. The discharge caused by canine glaucoma can appear as a crusty mucus discharge from your dog's eye. Intraocular pressure regulates the fluid that dictates the size of your dog's eye orb. With glaucoma, inadequate drainage raises the fluid in your dog's eye causing internal pressure.

A veterinary ophthalmologist uses a tonometer to measure the intraocular pressure of your dog's eye. If glaucoma is detected, treatment differs in accordance to the advancement of the disease. Medications to promote drainage, and decrease fluid production, are used in less severe cases and enucleation surgery, or eye removal, is recommended for advanced acute glaucoma. Pain medication for discomfort is often administered.

Canine Ocular Entropion

Entropion can cause a crusty discharge from your dog's eye. Entropion is a congenital malfunction in which your dog's eyelid turns inward and scrapes the cornea of his eye. While any breed may experience this characteristic, certain breeds have a predilection including the golden retriever, chow chow, Chinese shar-pei, Labrador retriever, Irish setter, great Dane, Rottweiler and collie.

Canine entropion treatment begins with an eye exam in which your veterinarian checks for damage caused by the dysfunctional eyelid. If your dog's eye is undamaged and operational, surgery is used to correct the eyelid malfunction. Surgery typically involves the removal of eyelid tissue, and sutures are used to ensure proper function. Antibiotic ointment or drops are administered from home during the weeks following surgery.