When sitting in a quiet theatre or a packed train, stifling a sneeze by holding the nose and closing the mouth may seem like the courteous option.
But doctors have warned against the polite practice, after a man ruptured the back of his throat while trying to contain the convulsive explosion of air.
The 34-year-old was admitted to hospital barely able to swallow or speak after pinching his nose and clamping shut his mouth to stop a sneeze.
When doctors examined him they also heard strange popping and crackling sounds, which extended from his neck all the way down to his ribcage.
A scan confirmed that that air from his lungs had bubbled its way into the deep tissue and muscles of the chest when it could not escape.
Ear, nose and throat specialists at the University Hospitals of Leicester NHS Trust released details of the man’s condition in BMJ Case Reports and warned that trying to contain a forceful sneeze could lead to ‘numerous complications’ and even a lethal brain aneurysm.
“Halting sneezing via blocking the nostrils and mouth is a dangerous manoeuvre, and should be avoided,” said lead author Dr Wanding Yang.
"It may lead to numerous complications, such as pseudomediastinum (air trapped in the chest between both lungs), perforation of the tympanic membrane (perforated eardrum), and even rupture of a cerebral aneurysm (ballooning blood vessel in the brain).”
Doctors said the man’s condition was similar to Boerhaave’s syndrome in which the esophagus is torn as a result of intense retching or vomiting. But in his case the build up of pressure from the trapped sneeze caused a rupture higher up in the throat, at the pharynx, which is situated just behind the tongue.
Sneezes are powerful, travelling up to 200 mph, according to MIT scientists, with the power to eject debris up to 25 feet.
Previously people have been admitted to hospital suffering from burst eardrums, ruptured blood vessels in the eyes, damaged facial nerves, pulled muscles and even cracked ribs from trying to contain the huge force.
Doctors say a sneeze, or sternutation, is intended to release foreign, and potentially damaging, particles, irritants or germs. Stopping it not only risks rupturing the throat, but could encourage the build of bacteria or trigger an asthma attack.
The patient was admitted to hospital where he was fed by a tube and given intravenous antibiotics until the swelling and pain had subsided.
After seven days the man, who has not been identified, was well enough to be discharged with the advice not to block both nostrils when sneezing in future.
And for people still needing to suppress a sneeze, experts advise rubbing the nose, breathing heavily through the nose, or rubbing the area above the lip.