DEAR DR. ROACH: I also have a dry cough that’s been going on for about 13-14 years. I’m a healthy 62-year-old and read that it is called “cough variant asthma.” I would like to know more about this but really can’t find anything about it, except that it will eventually get worse if it’s not treated. I was checked twice in the past 15 years for asthma, and I wasn’t diagnosed. However, I’ve not been diagnosed with any acid reflux or postnasal drip. — D.S.

ANSWER: Although most people think that asthma causes wheezing, cough is a very common symptom of asthma. You’ve named the two other most common causes of chronic cough: acid reflux and postnasal drip. It can be tricky to make these diagnoses.

Very often, primary care doctors will do a “therapeutic trial” that involves a short-term prescription to see if there is improvement. For acid reflux, it might be an H2 blocker like famotidine (Pepcid), which acts faster than a proton-pump inhibitor like omeprazole. This is often faster, easier, and much less expensive than a diagnostic test like a 24-hour pH monitor (the gold-standard diagnostic test).

Similarly, a physician might give a trial of asthma medication (such as a bronchodilator like albuterol) to see if it stops the cough, rather than immediately testing a person’s pulmonary function with a trial of bronchodilators — a standard diagnostic test for asthma. Sometimes a pulmonologist will order a “methacholine challenge test” where an airway irritant is given at very low doses to see if it will trigger an asthma response in the lung. Postnasal drip can sometimes be confirmed by a physical exam, but a fiberoptic laryngoscopy is seldom necessary to make the diagnosis.

When the therapeutic trials are not helpful, these diagnostic tests become necessary. I personally order lung testing before and after bronchodilators on all patients with suspected asthma, as the tests give important information beyond a diagnosis. Lung testing can be used to follow the course of the disease and identify whether there may be a separate problem in addition to asthma.

DEAR DR. ROACH: I am a 69-year-old male. I exercise five days per week and eat healthy. I take losartan, simvastatin, Xarelto and metoprolol. I have gotten the COVID and flu shots yearly but still end up catching the flu. What gives? — J.L.P.

ANSWER: I wish the flu shot was perfect, but it isn’t. Each year, the flu shot is usually around 30% to 50% effective at protecting people from getting the flu. Still, 50% protection is a lot better than no protection at all. Furthermore, if you do get the flu, people who have received the vaccine tend to have milder cases, which is very similar to the COVID vaccines.

The flu is pretty contagious, so if you are in close contact with a lot of different people, you are likely to get exposed. You can reduce your risk of the flu (and COVID) by keeping away from large groups or wearing a mask, in addition to getting your yearly vaccine.

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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.