A healthy 27-year-old man sitting in a car let out a long yawn. Soon after, the right side of his face stopped working normally. His right ear felt full, his cheek and tongue went numb, and he could not close his right eye.
Sudden weakness on one side of the face is one of the classic warning signs of stroke. In this man's case, after brain and ear imaging came back clear, doctors in Italy diagnosed something far rarer: alternobaric facial palsy, a pressure-related injury to the facial nerve usually tied to scuba diving, flying or altitude. He recovered fully within three weeks.
The case, from clinicians at the Universities of Verona and Padua, was published online in September 2025 in CRANIO and now appears in the journal's 2026 print volume. It shows how an everyday action can produce an unusual nerve problem, and why doctors do not jump to a harmless explanation when a face suddenly droops.
Ruling Out the Dangerous Possibilities First
On examination, the man had a right-sided peripheral facial palsy, graded IV on the House-Brackmann scale, which runs from I for normal function to VI for complete paralysis. He had a positive Bell's sign, meaning his eye rolled upward when he tried to close it. The rest of his neurological exam was normal.
CT and MRI scans of his brain and temporal bones, the skull bones that house the ear, showed no lesions, and other causes were ruled out.
Only then did the team settle on alternobaric facial palsy. It is a diagnosis of exclusion, reached because of the abrupt onset after a pressure-changing event, the lack of any structural problem and the elimination of other explanations.
He was treated with prednisone, starting at 50 milligrams and tapered over three weeks, along with eye protection and close follow-up. He recovered fully within three weeks and had no recurrence at 3, 6 or 12 months.
A Clue on the Forehead
Doctors use several features to tell a problem in the facial nerve itself from a problem in the brain. One of the most useful is the forehead.
The StatPearls reference on the condition explains that alternobaric facial paresis can cause an inability to wrinkle the forehead, close the eye, or smile evenly. It adds that sparing of the forehead suggests a central cause, like stroke, and does not fit this pressure-related palsy.
That rule of thumb helps clinicians, but the public should not rely on it. The American Stroke Association lists face drooping among the core stroke warning signs and urges people to call 911 right away, even if symptoms go away. Imaging and a full exam are what allowed this man's doctors to rule out stroke.
How Ear Pressure Can Silence a Facial Nerve
The facial nerve runs through a narrow bony canal that passes close to the middle ear. According to StatPearls, alternobaric facial paresis happens when pressure in the middle ear compresses the nerve, temporarily interrupting its function.
The condition is best known among divers and air travelers. Doctors in the Journal of Medical Case Reports described a 25-year-old man who developed temporary right-sided facial weakness during a flight after having nasal congestion and a sore throat beforehand. A 2023 systematic review in the Annals of Otology, Rhinology and Laryngology identified 49 published cases of the condition, with a mean patient age of 34 and 80% of patients male.
A review in a Chilean otolaryngology journal notes that the condition occurs in the setting of Eustachian tube dysfunction, gaps in the bony facial nerve canal and pressure changes. It adds that most episodes last minutes to a few hours before full recovery, and that the condition is probably underreported.
Why a Yawn Is Such a Strange Trigger
The yawning case stands out because yawning is normally part of the fix. StatPearls lists yawning and swallowing among the moves that equalize middle ear pressure and can make this palsy fade.
The Italian authors describe the yawn as an atypical trigger and say alternobaric mechanisms should be considered in sudden facial palsy, even in everyday settings. Their patient's weakness also lasted longer than the usual minutes-to-hours episode, taking weeks to resolve.
The report describes one patient, and the diagnosis rests on ruling out other causes rather than on a test that captured the pressure change. It does not suggest that yawning poses a meaningful risk for most people. Getting the diagnosis right still matters. StatPearls notes that divers with this palsy have been mistaken for having decompression sickness or air embolism, leading to unnecessary recompression treatment.
Anyone who develops sudden facial weakness, numbness, slurred speech, arm weakness, vision changes, or trouble walking should call 911 immediately rather than wait to see whether it passes. People who have had facial weakness during flights or dives should discuss it with a clinician, ideally an ear, nose and throat specialist, before their next trip or dive.
Key Questions Answered
What happened to the man?
After a long yawn in a car, the 27-year-old developed right-sided facial weakness, ear fullness, cheek and tongue numbness, and an inability to close his right eye.
What is alternobaric facial palsy?
It is a rare, usually temporary facial nerve problem caused by pressure changes in the middle ear. It is most often linked to diving, flying, or altitude.
How did doctors rule out stroke?
His neurological exam was otherwise normal, and CT and MRI of the brain and temporal bones showed no lesions.
Why does the forehead matter?
Weakness that spares the forehead suggests a brain cause such as stroke, while nerve-level palsies typically affect the forehead too. Only a clinician should make that call.
Did he recover?
Yes. With steroids and eye care, he recovered fully within three weeks and had no recurrence over 12 months.
What should someone do if their face suddenly droops?
Call 911 immediately. Sudden facial drooping is a stroke warning sign until proven otherwise.
Published by Medicaldaily.com
