TL;DR: Facial drooping in dogs is typically caused by nerve paralysis and requires a veterinary exam within 24 hours, though accompanying balance issues may indicate a neurological emergency.
What causes facial drooping in dogs and what does it look like?
If you have noticed that one side of your dog's face looks "heavy" or is sagging, they are likely experiencing facial nerve paralysis. This occurs when the nerve controlling the facial muscles—including the lips, eyelids, and ears—is damaged or inflamed. Common signs include:
- Inability to blink
- One ear hanging lower than the other
- Food and water falling out of the side of the mouth
When is facial drooping in dogs considered an emergency?
While facial drooping is generally classified as a Medium Urgency situation, you should follow these triage guidelines:
- Schedule a veterinary examination within 24 hours to identify the underlying cause.
- Seek emergency care immediately if the drooping is accompanied by severe balance issues, an inability to stand, or extreme lethargy.
How can taking a photo or video help my veterinarian?
Capturing a clear photo or short video of your dog's face can be a vital tool for your veterinary team because:
- Facial drooping can be subtle or fluctuate depending on your dog's activity level.
- A visual record allows the vet to see exactly what you are seeing at home.
- It helps the vet assess the severity of the paralysis and provides a baseline to track if the condition is improving or worsening over time.
Clinical Context (Merck Veterinary Manual)
Facial paralysis in dogs, characterized by asymmetry of facial expression, can result from unilateral or bilateral lesions of the facial nucleus or nerve. Complete paralysis involves an inability to move the eyelids, ears, lips, or nostrils, while paresis indicates reduced muscle movement. Clinical signs vary with the location, severity, and chronicity of the lesion. Idiopathic facial paralysis, a common disorder particularly in Cocker Spaniels, Pembroke Welsh Corgis, and Boxers, presents with acute onset of unilateral or bilateral inability to blink, drooping ear, drooping upper lip, and drooling, while facial sensation remains intact. Diagnosis of idiopathic facial paralysis is based on clinical features and exclusion of other causes, such as ear disease, trauma, and brain-stem lesions. Primary neoplasia of the facial nerve is rare, but neoplastic processes such as squamous cell carcinoma and polyps of the middle ear can affect the facial nerve, especially in cats. Treatment for idiopathic facial paralysis is generally supportive, such as artificial tear administration, as there is no specific therapy, and resolution can be spontaneous or permanent.
Chapter: Neurology
Source: The Merck Veterinary Manual, 11th Edition (Page 1239)