A clogged or ringing ear may belie a more serious health problem. On a cold summer evening in New York, Tom Gerety, then age 53, noticed something was up with his hearing. Over dinner with family, at a hotel in the Hudson Valley, he felt his right ear ringing and found himself straining to hear.

Gerety had spent the weekend swimming in a lake with his kids and at first thought, he had some leftover water clogging his ear canal. But after “several days of desperation” when jumping up and down, using a vacuum pump, and alcohol and cotton swabs failed to clear his ear he went to see his doctor.

The study was published in the journal JAMA Otolaryngology-Head & Neck Surgery.

The doctor told me, ‘You don’t have water in your ear. You have hearing loss, Gerety, an NYU law professor who was then the president of Amherst College, recalls. The diagnosis was a shock and sent Gerety into a “mild panic."

Gerety is one of the 66,000 Americans who are surprised each year by a diagnosis of an underappreciated and sometimes devastating condition: sudden sensorineural hearing loss, or sudden deafness. Suggests it isn’t as rare as some think occurring in up to 20 per 100,000 people.

Sudden hearing loss can belie a more serious medical problem

One reason a drop in the hearing should be treated as a medical emergency is that it might belie a more serious health problem.The precise cause of sudden deafness is still mysterious, but researchers have two main theories: One is that a virus leads to an inflammatory response in the inner ear and that inflammation stuns the sensory cells that enable hearing. A second theory is that decreased blood flow to the ear results in hearing loss.

A minority of cases are brought on by viral infections (from Lyme to measles, rubella, even tuberculosis), a head and neck tumor, circulatory problems, autoimmune diseases (like Lupus), or an inner ear disorder (like Ménière’s disease).

But when doctors rule out these potential factors taking a health history and doing a physical exam and an MRI, they find the vast majority of patients (85 to 90%) have no identifiable cause for their hearing loss.

People can adapt to the new hearing normal

The hearing loss that results from sudden deafness can range from mild to severe. And that’s another reason sudden deafness requires urgent care: It can sometimes be reversible.

But patients need to seek immediate care to experience these potential benefits. And, unfortunately, people with more profound hearing loss are less likely to benefit from treatment. Still, he’s managed to get used to the new normal in his ears. Luck favored me with a good durable hearing on the other side.

A simple to test to tell if you have a sudden hearing loss

You probably have a temporary hearing loss from wax, fluid, or water, and your hearing will return when your cold goes away, or the wax clears. But if your voice sounds louder in the good ear, “you have an emergency and need to be seen by an ENT.