Has your dog suddenly developed a lopsided smile? Facial paralysis in dogs is a condition that is characterized by changes in your dog's expression and facial control. If your dog is looking like a canine Harvey Dent, don't worry. Most cases have a favorable outcome even if some dogs require extra care following their diagnosis. Read on to learn about the causes and management of this condition.

Causes of Facial Paralysis
Facial paralysis results from damage to a facial nerve called cranial nerve VII. This nerve is connected to the muscles that control your dog's eyelids, lips, nose, ears and cheeks, and when it's damaged a portion of his face can appear frozen or droopy. The effects of nerve damage may persist for an extended or indefinite period of time.
Cocker spaniels, beagles, corgis and boxers are more frequently affected during their mature years compared to other breeds. Depending on the underlying cause, temporary facial paralysis in dogs can last several weeks. Possible causes of facial paralysis include:
- Middle and inner ear infections
- Trauma to the head
- Endocrine disorders (hypothyroidism, diabetes mellitus, Cushing's disease)
- Toxins, including botulism, which is used to synthesize Botox and which dogs can get from eating raw meat, according to Wag!
- Tumors, especially growths that invade or compress cranial nerve VII or the brainstem
Surprisingly, the majority of cases of facial paralysis in dogs are idiopathic and not traceable to a specific cause. A slim margin can also be iatrogenic, or accidentally caused during surgery.
Signs
Depending on the underlying cause, the signs of facial paralysis in dogs can manifest on one or both sides of the face. Pet parents familiar with Bell's Palsy, a form of facial paralysis in people that the Mayo Clinic notes also includes nerve damage, will notice a similar change in the appearance of their dog's face. The common signs of damage to cranial nerve VII include:
- Drooling (the facial nerve also controls the salivary glands)
- Drooping of the lip and ear
- Deviation of the nose toward the unaffected side
- Inability to blink and close the affected eye
- Sloppy eating, dropping food from mouth
- Eye discharge
If you suspect your dog has facial nerve paralysis, contact your veterinarian. They will perform a comprehensive physical exam of your dog's eyes, ears and motor coordination and check for other cranial nerve and systemic neurological problems.
Looking Out for Dry Eye
An important part of your vet's exam will be testing your dog's ability to blink with the eye on the affected side of his face. Pet Health Network notes that a significant risk of facial nerve paralysis in dogs is keratoconjunctivitis sicca, commonly known as dry eye. This condition develops when a dog can't produce enough tears or close the affected eye.
Your vet may conduct an exam called the Schirmer tear test to see if your dog's eyes are producing enough lubrication. They may prescribe artificial tears since dogs with dry eye are at risk for developing corneal ulcers.
