Dropped Jaw (Trigeminal Neuropathy) in Dogs

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Last updated on
4 min read

Key takeaways

Dropped jaw (trigeminal neuropathy) is a disorder of the cranial nerve that controls the movement and sensitivity of the jaw in dogs.

  • The characteristic symptom is the inability to close the mouth
  • Jaw dysfunction is often accompanied by drooling and difficulty swallowing
  • Causes are not well understood at this time
  • Dogs that cannot close their mouths require prompt veterinary attention
  • Diagnostic tools include physical examination, blood work, urinalysis, and head MRI
  • Trigeminal neuropathy is a self-limiting condition that usually runs its course within four weeks
  • While symptoms are present, supportive therapy is necessary to maintain fluid and caloric intake, and avoid atrophy of the jaw muscles
  • Prognosis is good in most cases
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A closer look: Dropped Jaw (Trigeminal Neuropathy) in Dogs

The severity of trigeminal neuropathy depends on how long it takes the disorder to run its course. There is no cure, but movement and sensation return without treatment within 2 to 10 weeks. Since the dropped jaw limits the ability to eat, the severity of the condition depends on a dog’s ability to maintain sufficient nutrition and hydration. Longer recovery periods may also lead to atrophy of the muscles in the jaw in some cases. In certain instances, trigeminal neuropathy is associated with Horner’s syndrome (a nerve disorder of the eyes), weakness in other muscles of the face, and decreased facial sensation.

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Risk factors

Trigeminal neuropathy is uncommon in dogs. It is not life-threatening, and usually resolves within 4 weeks. Dogs with difficulty closing their mouths require prompt veterinary attention to determine a supportive therapy strategy.

While the condition is present, affected dogs may lose weight due to difficult eating. It is important to seek veterinary guidance so the nutritional impact of difficulty eating is minimized.

Trigeminal neuropathy affects all breeds, genders, and ages alike.

Possible causes

The causes of trigeminal neuropathy are not fully understood at this time. Current theories include inflammation or auto-immune disease which affects the trigeminal nerve (the nerve that controls the jaw) temporarily, disrupting the impulses sent by the brain. Without appropriate messaging from the brain, the jaw hangs open. This symptom is why this disorder is also known as dropped jaw.

Main symptoms

The characteristic symptom of trigeminal neuropathy is the inability to close the mouth.

Testing and diagnosis

Testing and diagnosis

Diagnosis of trigeminal neuropathy is challenging to confirm, and is usually assumed based on the characteristic symptom of the dropped jaw. Diagnostic tools include:

  • Physical examination
  • Bloodwork
  • Urinalysis
  • MRI of the head
  • Spinal tap
  • Muscle biopsy

Steps to Recovery

There is no treatment for trigeminal neuropathy. The disorder resolves on its own, and usually runs its course within 4 weeks. Supportive therapies are required to maintain caloric and fluid intake, as well as exercise the muscles of the jaw to avoid atrophy. Strategies include:

  • Feeding wet meatballs of food or gruel consistency food by hand
  • Using a feeding tube
  • Performing range of motion exercises of the jaw
  • Encouraging chewing with toys where possible

Periodic monitoring of symptoms, body weight, nutritional status, and hydration are necessary while symptoms are present.

Trigeminal neuropathy is self-limiting and usually runs its course in as few as two and as many as ten weeks. The prognosis is good in most cases. Severely affected dogs need longer to recover and their prognosis is more guarded.


There are no proven preventative measures for trigeminal neuropathy. The condition is not contagious.

Is Dropped Jaw (Trigeminal Neuropathy) in Dogs common?

Trigeminal neuropathy is uncommon in dogs.

Typical Treatment

Management for nutrition, hydration and muscle maintenance.

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