Yawn-Induced Facial Palsy: A Rare Case of Alternobaric Facial Nerve Injury

A 27-year-old man experienced sudden facial paralysis on the right side of his face immediately after letting out a long yawn while sitting in a car. His right ear felt blocked, his cheek and tongue lost sensation, and he found himself unable to close his right eye.

Sudden facial weakness is a well-known warning sign of stroke, necessitating immediate medical evaluation. In this patient’s case, after brain and ear imaging returned normal, clinicians in Italy diagnosed a much rarer condition: alternobaric facial palsy. This pressure-related injury to the facial nerve is typically associated with scuba diving, flying, or high-altitude exposure. The patient made a complete recovery within three weeks.

Reported by clinicians at the Universities of Verona and Padua, the case was published online in September 2025 in the journal CRANIO and is featured in the 2026 print volume. It highlights how a mundane, everyday action can trigger an unusual nerve injury, underscoring why physicians must carefully rule out serious conditions before settling on a benign diagnosis when a patient presents with sudden facial drooping.

Ruling Out the Dangerous Possibilities First

Upon clinical evaluation, the patient presented with right-sided peripheral facial palsy, classified as Grade IV on the House-Brackmann scale—a grading system ranging from I (normal function) to VI (complete paralysis). He exhibited a positive Bell’s sign, where the eye rolled upward upon attempted closure. The remainder of his neurological examination was unremarkable.

CT and MRI scans of the brain and temporal bones—the skull structures containing the ear—revealed no structural lesions, and other potential causes were systematically ruled out.

Only after excluding these possibilities did the medical team conclude that the patient had alternobaric facial palsy. This is a diagnosis of exclusion, established based on the sudden onset following a pressure-altering event, the absence of structural abnormalities, and the exclusion of other potential causes.

The patient was treated with a three-week course of prednisone, starting at 50 milligrams and gradually tapered, alongside protective measures for the eye and close clinical monitoring. He achieved a full recovery within three weeks, with no signs of recurrence at the 3-, 6-, or 12-month follow-ups.

A Clue on the Forehead

Clinicians rely on several physical signs to differentiate between peripheral facial nerve damage and central neurological issues, with the forehead providing one of the most valuable diagnostic clues.

According to medical literature on the condition, alternobaric facial paresis can impair the ability to wrinkle the forehead, close the eye, or smile symmetrically. In contrast, sparing of the forehead typically points to a central cause, such as a stroke, which is inconsistent with a pressure-related nerve injury.

While this clinical distinction is highly useful for physicians, the public should not attempt self-diagnosis. The American Stroke Association identifies facial drooping as a primary warning sign of stroke and advises calling emergency services immediately, even if the symptoms resolve on their own. Comprehensive imaging and clinical examination are essential to rule out stroke, as was successfully done in this patient’s case.

How Ear Pressure Can Silence a Facial Nerve

The facial nerve travels through a narrow bony canal in the skull that runs in close proximity to the middle ear. Medical sources note that alternobaric facial paresis occurs when rapid pressure changes in the middle ear compress the nerve, temporarily disrupting its normal function.

This condition is most commonly observed in scuba divers and air travelers. For instance, case reports have documented temporary facial weakness in a 25-year-old man during a flight, triggered by pre-existing nasal congestion and a sore throat. A 2023 systematic review published in the Annals of Otology, Rhinology and Laryngology identified 49 documented cases of the condition, showing a mean patient age of 34 years, with 80% of those affected being male.

A review in a Chilean otolaryngology journal highlights that the condition typically arises in the context of Eustachian tube dysfunction, anatomical variations or gaps in the bony canal housing the facial nerve, and significant pressure fluctuations. Most episodes resolve within minutes to a few hours, though researchers suggest the condition is likely underreported.

Why a Yawn Is Such a Strange Trigger

The reported case is unusual because yawning is typically part of the physiological solution, not the cause. Medical references list yawning and swallowing as natural actions that help equalize middle ear pressure and can alleviate pressure-related nerve palsies.

The Italian clinicians characterized the yawn as an atypical trigger, emphasizing that alternobaric mechanisms should be considered in cases of sudden facial palsy, even in everyday, non-travel contexts. Additionally, the patient’s symptoms persisted for weeks, significantly longer than the typical minutes-to-hours duration usually associated with the condition.

As a single-patient case study, the diagnosis relies on excluding other potential causes rather than direct visualization of the pressure shift. The authors clarify that yawning does not pose a significant risk to the general population. However, obtaining an accurate diagnosis remains critical; in some instances, divers with alternobaric facial palsy have been misdiagnosed with decompression sickness or air embolism, leading to unnecessary recompression therapy.

Individuals who experience sudden facial weakness, numbness, slurred speech, arm weakness, vision changes, or difficulty walking should seek emergency medical attention by calling 911 immediately rather than waiting for symptoms to resolve. Furthermore, anyone who has experienced facial weakness during flights or diving should consult a physician—ideally an ear, nose, and throat specialist—before future travel or diving.

Key Questions Answered

What happened to the man?

Following a prolonged yawn while in a car, the 27-year-old developed right-sided facial weakness, a sensation of fullness in the right ear, numbness of the cheek and tongue, and an inability to close his right eye.

What is alternobaric facial palsy?

It is a rare, typically transient condition affecting the facial nerve, resulting from rapid pressure changes within the middle ear. It is most frequently associated with scuba diving, flying, or exposure to high altitudes.

How did doctors rule out stroke?

The patient’s neurological examination was normal apart from the facial palsy, and CT and MRI scans of the brain and temporal bones showed no lesions or structural abnormalities.

Why does the forehead matter?

Facial weakness that spares the forehead often indicates a central neurological cause, such as a stroke, whereas peripheral nerve palsies generally affect the forehead as well. This distinction should only be made by a qualified medical professional.

Did he recover?

Yes. With a course of steroids and protective eye care, the patient achieved a full recovery within three weeks, with no recurrence observed over a 12-month follow-up period.

What should someone do if their face suddenly droops?

Call 911 immediately. Sudden facial drooping is a key indicator of stroke and must be treated as a medical emergency until proven otherwise.

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