Differentiating Facial Weakness Caused by Bell’s Palsy vs. Acute Stroke

By AOO on October 4, 2021 under Healthcare

Differentiating Facial Weakness Caused by Bell’s Palsy vs. Acute Stroke

Bell’s Palsy and ischemic stroke are the two most common causes of acute facial paralysis. Most ordinary people know that strokes cause facial weakness and will call emergency services if they suddenly find they have trouble smiling with one side of their face, for example. But how do you know whether you are indeed suffering from an acute ischemic stroke or Bell’s Palsy, another condition with a similar presentation?

The most important clue lies in which parts of the face demonstrate weakness. Other relevant information includes age, how quickly the symptoms appeared, and the presence of any additional concurring symptoms.

Difference in Patterns of Facial Weakness


A stroke occurs due to the blockage of a blood vessel in the brain. Motor neurons traveling from the cortex of either brain hemisphere stimulate facial muscles on the opposite side of the body. Thus, when a stroke impacts one hemisphere of the brain, it will cause facial weakness in the opposite side of the face. This usually presents as having difficulty smiling and the nasolabial fold may appear flattened.

Bell’s Palsy

Facial paralysis attributed to Bell’s Palsy develops due to lesions affecting the facial nerves originating from the brain stem. The left and right facial nerves control all facial muscles. When lesions damage a facial nerve, one entire side of the face weakens. This leads to difficulty smiling, raising your eyebrows, wrinkling your forehead, and closing your eye tightly. Their nasolabial fold may also appear flattened.

Stroke Near the Brain Stem

If a stroke involves the brain stem, the effects can resemble those caused by Bell’s Palsy. A patient suffering from a stroke will, however, experience other neurological symptoms. So, to diagnose definitively, a health professional must consider other factors besides facial weakness patterns.

Associated Signs and Symptoms

The following are additional symptoms of an acute ischemic stroke that are NOT associated with Bell’s Palsy.

  • Weakness/numbness in the arm or leg
  • Double vision
  • Slurred speech
  • Difficulty swallowing
  • Facial numbness
  • Vertigo
  • Ataxia (lack of coordination)

Onset of Symptoms

Another significant difference between these conditions is how rapidly the onset of symptoms occurs and worsens. In the case of a stroke, the onset of symptoms happens quickly, reaching maximum severity in a matter of seconds to minutes. Bell’s Palsy symptoms, by contrast, advance over hours to days.


While not definitive, a patient’s age can indicate whether they are at a higher risk for Bell’s Palsy or stroke. Bell’s Palsy patients are typically in their 30s to 50s. Patients over 60 are most at risk for acute ischemic strokes.

What to do if you experience a facial weakness or droop?

If you or someone you know experiences a sudden drop in their facial expression they should seek urgent or emergency care immediately. A skilled provider should be able to differentiate a concern of stroke versus Bell’s palsy. If there is a concern for stroke, then imaging and urgent intervention with a neurologist should be done in a timely manner.   An otolaryngologist or ENT physician should only be seen when it has been determined to be a Bell’s palsy. ENT physicians do not treat strokes. However, AOO/ENT Specialists of the Rockies are specialists in the facial nerve and have experts in treating Bell’s palsy and other peripheral nerve injuries of the face.   They would be an appropriate follow-up after urgent or emergent assessment.

Facial Paralysis Treatment in

AOO/ENT Specialists of the Rockies is your resource for expertise in ear, nose, and throat health.  We are experts in the facial nerve and have specialists in facial reconstruction and nerve injuries such as Bell’s palsy.  Our board-certified physicians and ENTs have been treating patients and building trust with multiple generations of families for over 40 years. We have three convenient locations in Denver, Lone Tree, and Castle Rock, Colorado. To schedule a consultation, please call the nearest location or fill out our online form.