Have you heard of “facial palsy” in dogs?
This is a surprisingly common condition in middle-aged or older dogs, and yet few people are aware of it.
The first many people know is that their dog “doesn’t look right.” The change often happens suddenly: The dog wakes in the morning, eats breakfast more messily than usual, dropping food from one side of the mouth. Then, when their human stares more closely, they realize the dog has a droopy face on one side.
A Lopsided Expression
Telltale signs that a dog has facial palsy include:
- Usually only 1 side of the face is affected.
- One side of the lip hangs down lower than the other.
- One ear is more limp than the other.
- The nose is drawn to the opposite side.
- One eyelid is more droopy than other.
- The dog blinks less frequently on the affected side.
- The surface of the eye becomes dry and inflamed.
- Food gets stuck in 1 side of the mouth.
Indeed, the most common reason people take their dog to the vet with this condition is that their face is drooping.
The Facts of Facial Palsy
Another term for facial palsy is facial paralysis. The latter better reflects that this is an issue with the nerve supply to the muscles and senses on that side of the head.
To better understand this, think of the nerves as the electrical wiring supplying a light switch (the muscles). If there’s damage to the wiring, you can press the switch all you like, but the light still won’t come on.
With facial paralysis, inflammation — from the nerves to the muscles of the face — stops them from working. The muscles themselves are fine but aren’t getting any messages telling them to work. The result is slack muscles, lacking in tone and that characteristic facial droop.
But those facial nerves don’t just supply muscle; they also service:
This is why the dog may develop a dry mouth on the affected side due to lack of saliva or a dry eye due to lack of tear production.
Causes of Facial Palsy in Dogs
At this point, you might be drawing a comparison with people and wondering if the dog has had a stroke. But in that wonderful way that pets are different from people (and why human doctors aren’t allowed to treat animals), a stroke rarely causes a droopy-faced dog.
Around 1/4 of all canine cases are down to 1 of the following:
- Hypothyroidism: This refers to a lack of thyroid hormone, leading to a general slowing of the metabolism.
- Middle or inner ear infections: The facial nerves pass through the inner ear on their way to the face. Inflammation in the inner ear pinches the nerves and stops them from working.
- Inflammatory conditions: These include meningitis or sterile inflammation of the nervous system.
- Trauma: A knock or blow to the head can cause pressure and inflammation.
- Brain tumor: Happily, this is a rare cause.
- Poor blood supply: Poor circulation to the nerves means they don’t function as well.
So if the above accounts for 25% of cases, what is the single biggest reason accounting for 75% of cases? Well, 3 out of every 4 dogs with facial paralysis are diagnosed with idiopathic facial nerve paralysis (IFNP). The long, intimidating word “idiopathic” means “no one knows the reason.” In other words, for the majority of facial palsy dogs, no reason is found.
If it’s your dog who’s affected, this all sounds rather unsatisfactory. How can it be that no one has the answer? Well, it isn’t for lack of trying — the full weight of modern technology, such as CT and MRI scans, has been thrown behind this, and still no one’s the wiser.
OK, so maybe I’m oversimplifying things slightly, because nerve inflammation does seem to be involved. But again, no one is certain why the nerve inflammation happens in the first place, so we end up back with that word “idiopathic” again.
Treating Facial Palsy
This is a good news/bad news scenario.
The bad news is that if your dog is in the 75% of cases where no other problem is found, then there is no specific treatment. However, the good news is that the condition is unlikely to bother the dog greatly, and may — just may — slowly improve with time.
For those “idiopathic” cases, nothing is proven to help. For a while, steroids were in fashion (to help reduce inflammation), but there’s no conclusive evidence they help, and so now they’re out of vogue. The only thing that may help is to put artificial tears into the affected eye to stop the cornea drying out from lack of tear production.
And as for the other 25%, if an underlying problem is found, then treating that is going to help. However, even then the palsy may be permanent and only improve slightly over time.
Learn more about canine hypothyroidism, a possible cause of facial palsy, in this video:
Testing Your Dog
Your dog’s droopy face may be a cry for help and a warning they have underactive thyroid glands or a deep-seated ear infection. Treating these conditions will greatly improve their quality of life and prevent deterioration in the facial paralysis.
However, be prepared for the fact that you may spend big on tests only to have the vet give you the all clear. But there again, this is a good thing (except, perhaps, for your bank balance).
So if one day your dog wakes up with a droopy face, don’t panic, but do get them checked out by a vet.
This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed May 11, 2018.
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