Facial Paralysis in Dogs

Facial paralysis in dogs is the inability to move eyelids, ears, lips or nostrils as a result of various types of damage to the facial nerve or nucleus. This damage causes the muscles to lose tone and inhibits their ability to move and function as designed.

These muscles help with blinking, moving the ears, and “smiling.” When this nerve is not functioning, the facial muscles become weak or, in some cases, completely paralyzed. In turn, the face begins to droop or “sag.” You may also notice that your dog doesn’t blink as much.

Sometimes dogs can drool excessively from one side of the mouth. Dogs have both a right and left facial nerve that supplies each side of the face. One side or both sides may be affected.

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

Causes of Facial Paralysis in Dogs

The most common cause of facial nerve paralysis in dogs is idiopathic facial nerve paralysis. The term idiopathic means that there is no known cause. Therefore, in idiopathic disease all the tests results will be normal. A similar condition is recognised in human medicine as Bell’s Palsy.

The second most common cause of facial nerve paralysis is a deep-seated infection of the ear (otitis media/interna). In this case, other signs such as Horner’s syndrome (decreased pupil size and third eyelid coming across the eye) and/or vestibular syndrome (head tilted to one side, and balance loss) (see related fact sheet) are frequently seen in addition to facial paralysis.

Signs and Symptoms of Facial Paralysis in Dogs

A dog or a cat with facial paralysis has a drooping appearance of the face on one side (a bit like a person that has suffered a stroke, however the underlying cause here is totally different). One ear is held lower than the other and the lip hangs down on the affected side. Affected dogs are unable to blink and have a tendency to dribble saliva and drop food from the side of the mouth. Occasionally, the same signs may be present on both sides of the face, which can make the changes difficult to recognise.

Diagnosis

Although idiopathic facial nerve paralysis is the most common form of this disease. Investigations may be required to rule-out any other causes. Your vet will first want to perform a thorough ear examination (if necessary under sedation or anaesthesia using a scope). This is to detect signs of ear infection (such as a ruptured eardrum or an inflamed ear canal).

If this examination is normal then the deeper parts of the ear and brain may be examined using specialised imaging techniques. The deeper part of the ear can be seen on X-Rays of the skull and the back of the brain can be examined using CT or MRI scans. In some cases it may be necessary to take a sample of fluid from around the brain to check for signs of inflammation.

Treatment of Facial Paralysis in Dogs

Again the most common cause of FNP is the idiopathic form where no identifiable cause is determined. Hence treatment is supportive rather that directed at a specific cause. One of the key elements of treatment is keeping the eye lubricated with artificial tears. This treatment is usually long term as most of these patients never fully recover. The benefit of corticosteroids is not known in veterinary medicine for this condition. Though it can have a positive effect in humans with Bell’s palsy.

Of course patients with middle ear infections or low thyroid levels can be treated specifically. Although hypothyroid dogs may never return to normal relative to the FNP.