Diagnostic Differences Between Bell's Palsy and Stroke

Primary Diagnostic Features

The American Academy of Otolaryngology-Head and Neck Surgery notes that Bell's palsy causes weakness of both the upper and lower face, including forehead, while stroke causes weakness of only the lower face with forehead sparing due to bilateral cortical innervation of the upper facial muscles 1, 2
Bell's palsy is characterized by unilateral facial weakness involving the forehead, inability to raise eyebrow, and wrinkle forehead on the affected side, with rapid onset over less than 72 hours 2
Patients with Bell's palsy can close their eye on the affected side, though incompletely, and may have ipsilateral ear/face pain, hyperacusis, and taste disturbance on the anterior two-thirds of the tongue 2
The American Academy of Otolaryngology-Head and Neck Surgery recommends that no other neurological deficits should be present in Bell's palsy, such as limb weakness, sensory changes, diplopia, or dysphagia 3, 4

The American Academy of Otolaryngology-Head and Neck Surgery suggests that symptom progression beyond 72 hours may indicate tumor or infection, and bilateral facial weakness is extremely rare in Bell's palsy, considering Guillain-Barré or sarcoidosis 1, 2, 3, 5
A history of head/neck cancer, isolated branch paralysis, and recent travel to endemic areas for Lyme disease should be considered in the diagnosis of Bell's palsy 2, 4, 6

The American Academy of Otolaryngology-Head and Neck Surgery recommends oral corticosteroids within 72 hours of onset for Bell's palsy, with an 83% recovery rate at 3 months compared to 63.6% with placebo 6
Eye protection is mandatory for patients with Bell's palsy, including lubricating drops, ointments, moisture chambers, eye patching, and sunglasses 2
Immediate activation of stroke protocol, time-sensitive thrombolytic therapy, or thrombectomy is necessary for stroke treatment, with admission for monitoring and secondary prevention 4, 5, 6