Patients with Bell palsy present with inability to close the eye, inability to raise the corner of the mouth, and often difficulty controlling saliva drainage from the affected side. This is often caused by reactivation of herpes simplex virus or herpes zoster infection.
In contrast to peripheral lower motor neuron palsy, facial palsy can be caused by an upper motor neuron lesion such as a stroke or mass lesion and typically only affects the lower portion of the face. Bilateral facial nerve palsy may be seen in the setting of infections such as Lyme disease. Findings of additional cranial neuropathies should prompt consideration of diagnoses other than Bell palsy.
Severe hypertension has been associated with facial palsy, particularly in children but also in adults. In children, there may be a substantial delay to diagnosis of hypertension; one study notes a median time of 45 days between the first symptoms of peripheral facial palsy and a diagnosis of arterial hypertension. Another study reports that adults with uncontrolled hypertension due to poor medication compliance have a higher incidence of Bell palsy.
G58.0 – Other disorders of facial nerve
280816001 – Facial Palsy
Differential Diagnosis & Pitfalls
- Myasthenia gravis
- Facioscapulohumeral muscular dystrophy
- Myotonic dystrophy
- Oculopharyngeal muscular dystrophy
- Lyme disease
- Human immunodeficiency virus (HIV) infection
- Herpes zoster infection
- Otitis media
- Neurosarcoidosis (see sarcoidosis)
- Leptomeningeal carcinomatosis
- Guillain-Barré syndrome
- Sjögren syndrome
- Mass lesion (temporal bone, parotid gland, cerebellopontine angle, brain stem)