You might know a habitual hacker or could be one yourself—someone whose cough won't go away no matter how many doctors have looked for a cause and tried different treatments. Weeks turned long ago into months, then years.

Such individuals represent 1 in every 10 patients referred to practices that specialize in respiratory disorders. Some chronic coughers—generally defined as someone who has been coughing for at least three weeks—break their ribs or, embarrassingly, leak urine occasionally. That's not so surprising; a full-throated cough has 500-mile-per-hour propulsive power, putting enormous stress on bones and tissue.

Now a Mayo Clinic study, presented today in Montreal at the annual meeting of the American College of Chest Physicians, suggests that some chronic coughers have sinusitis, or inflamed sinuses, a condition that might have been diagnosed if a CT scan had been ordered. Drugs or surgery can usually treat sinusitis successfully.

A team led by Kaiser Lim, a pulmonologist and allergist who runs Mayo's chronic cough clinic, studied the records of all patients who had come to the medical center in a recent 12-month period because of prolonged coughing—on average, they'd been suffering for more than four years. (Lim has had patients who have been coughing for 50 and 60 years.) The researchers focused on 132 patients who had received a CT scan of their sinuses. Radiologists who scrutinized the scans found that more than 35 percent of the scans showed strong evidence of sinusitis, and many of the others were suggestive.

Some doctors don't order a CT scan because they're not programmed to look specifically for sinusitis. It's not called out as one of the three accepted causes of chronic cough. The triad is postnasal drip syndrome, asthma, and gastroesophageal reflux disease (GERD), in which stomach acid splashes up the esophagus and irritates the throat.

Doctors zeroing in on postnasal drip, says Lim, tend to look only at rhinitis—inflammation of the inner lining of the nose, usually because of a cold or allergy—and not sinusitis, which also produces the unpleasant back-of-the-throat drip. Professional medical societies, says Lim, "have lumped sinusitis and rhinitis together, and chronic sinusitis is a difficult problem by itself." One of the study's messages for physicians, he says, is that if a patient doesn't respond to treatment for rhinitis and asthma and reflux, "don't forget sinusitis."

But mainly, says Lim, the reason people cough for years is that "it crosses so many specialties—gastroenterology, ENT [ear, nose, and throat], pulmonology. Physicians look at this through the window of their own expertise. So many times, patients see a specialist who says, 'I don't see anything here that pertains to me, so go see somebody else.' I call chronic cough a wastebasket of disease."

Even those who came to Mayo with a diagnosis often hadn't been treated appropriately. "If they were treated for GERD, they might have only gotten two weeks' worth of medication," says Lim, "or just limited use of an inhaler if they were diagnosed with asthma. I've seen patients on inhaled steroids for two years because the doctor didn't know what else to do."

Patients learn to live with their cough, but it exacts a toll. The Mayo team separately surveyed 136 chronic coughers and found that one third of those younger than age 65 had a spouse or roommate move out of the bedroom. A fifth of the patients said worry that the cough might indicate a serious illness was a major problem. Almost 8 in 10 expressed frustration or anger; the same proportion reported exhaustion or poor concentration. And more than 4 in 10 indicated some problem with urinary or fecal incontinence.

If someone with an ongoing cough isn't getting help, "the patient needs to ask the doctor whether there is somebody in the area who has an interest in chronic cough," says Lim. "The problem is that even in large metropolitan areas, there aren't many people like that. There isn't that much interest. Nobody dies from chronic cough. NIH won't fund it. One of the things we're trying to do is raise consciousness in this regard."