Chronic Cough Workup: How to Diagnose GERD, Asthma, and Postnasal Drip
Dec, 15 2025
If you’ve been coughing for more than eight weeks, you’re not alone. About 1 in 10 adults deal with a chronic cough, and most of the time, it’s not because of a cold or the flu. It’s usually one of three things: GERD, asthma, or postnasal drip-now more accurately called upper airway cough syndrome. The good news? These are treatable. The better news? You don’t need a dozen tests to find out which one it is.
Start with the basics: What’s really going on?
Before jumping into tests, your doctor needs to rule out the obvious dangers. If you’re coughing up blood, losing weight without trying, running a fever, or have swelling in your legs, that’s a red flag. These could point to something serious like lung cancer, tuberculosis, or heart failure. A chest X-ray is the first real test you’ll get-not because it’s fancy, but because it’s fast, cheap, and rules out big problems. If it’s normal, you’re likely dealing with one of the three common causes.Step 1: Rule out medications
Many people don’t realize their cough started after a new pill. ACE inhibitors-drugs like lisinopril or enalapril, often prescribed for high blood pressure-cause cough in 5 to 35% of users. It usually shows up within weeks to months. If you’re on one of these and have a dry, tickly cough, switching to a different blood pressure med can clear it up in days. No need for a long workup. Just ask: “Could this pill be making me cough?”Step 2: Look at the big three
After ruling out red flags and medications, doctors focus on the big three: upper airway cough syndrome (UACS), asthma, and GERD. Together, they cause 80 to 95% of chronic cough cases in nonsmokers. The trick? You don’t need to test them all at once. You test them one at a time, with treatment trials.Upper Airway Cough Syndrome (Postnasal Drip)
This is the most common cause, making up 38 to 62% of cases. It’s not just mucus dripping down your throat. It’s inflammation in your nose or sinuses that triggers your cough reflex. You might have a runny nose, frequent throat clearing, or feel like something’s stuck in your throat. But here’s the catch: you might not notice any nasal symptoms at all. The test? A two- to three-week trial of a first-generation antihistamine like brompheniramine or diphenhydramine, plus a decongestant like pseudoephedrine. These aren’t the non-drowsy ones you buy over the counter-they’re the older, sleepier versions that actually work better for cough. If your cough improves within a week or two, you’ve got UACS. Success rate? 70 to 90% when the diagnosis is right.Asthma (Cough Variant Asthma)
About 24 to 29% of chronic cough cases are caused by asthma-but you might not wheeze, and you might not feel short of breath. This is called cough variant asthma. The only symptom? A cough that gets worse at night, after exercise, or around cold air or allergens. The test? A spirometry test. It measures how much air you can blow out and how fast. If it’s normal, you might still have asthma. The next step is a methacholine challenge. You inhale a mist that mildly irritates your airways. If your lungs react by narrowing (a 12% drop in FEV1), you have asthma. You’ll also get a trial of an inhaled corticosteroid-like fluticasone-for four weeks. If your cough drops by half or more, it’s asthma. Response rate? 60 to 80%.
GERD (Gastroesophageal Reflux Disease)
GERD is responsible for 21 to 41% of chronic cough cases. But here’s the twist: up to 70% of people with GERD-related cough don’t have heartburn. It’s silent reflux. Stomach acid reaches your throat and voice box, irritating the nerves that trigger coughing. The test? A four- to eight-week trial of a high-dose proton pump inhibitor (PPI) like omeprazole 40 mg twice daily. No food for two hours before bed. No coffee, alcohol, or spicy meals. If your cough improves by 50% or more, GERD is likely the cause. But here’s the catch: only 50 to 75% of people respond. That’s because not all reflux causes cough, and some people’s cough is just hypersensitive.Why not just test for reflux with a pH probe?
You can. But it’s not usually the first step. A 24-hour pH impedance test shows if acid is coming up into your esophagus. But in chronic cough, it only picks up abnormalities in 50 to 70% of cases. And it’s expensive, uncomfortable, and often denied by insurance unless you’ve already tried PPIs. The American College of Gastroenterology now says: don’t test first. Treat first. If the PPI doesn’t work, then consider the probe.What if none of these work?
About 10 to 30% of people don’t improve after trying the big three. That’s when you dig deeper. Possible causes include:- Chronic bronchitis (if you’re a smoker)
- Pertussis (whooping cough)-rare in adults, but possible
- Chronic aspiration (inhaling food or saliva)
- Eosinophilic bronchitis (inflammation without asthma)
- Chronic refractory cough (CRC)-a condition where the cough reflex is overly sensitive
What to expect during treatment
Each trial takes time. Don’t expect overnight results.- UACS: Improvement in 1 to 2 weeks
- Asthma: Improvement in 2 to 4 weeks
- GERD: Improvement in 4 to 8 weeks
What doesn’t work
Antibiotics? Almost never. Only 1 to 5% of chronic cough is caused by bacterial infections like pertussis, and even then, you need a special nasal swab to confirm it. Most people get antibiotics anyway-and they don’t help. Chest CT scans? Not needed if your X-ray is normal. A CT exposes you to the radiation of 74 chest X-rays. And in people with normal X-rays, it finds cancer in only 0.1% of cases. Cough suppressants like dextromethorphan? They might dull the cough, but they don’t fix the cause. You’ll still be coughing in six months.Tools that help
There are simple questionnaires your doctor might use:- HARQ (Hull Airway Reflux Questionnaire): Scores over 13 suggest laryngopharyngeal reflux with 80% accuracy.
- Hull Cough Questionnaire: Scores over 15 mean your cough is severely affecting your life-sleep, work, socializing.
What’s new in 2025
The field is changing. Doctors are moving away from the term “postnasal drip.” It’s now called upper airway cough syndrome because it’s not about mucus-it’s about nerve sensitivity. Similarly, “silent reflux” is being recognized as a distinct problem from classic GERD. AI is also stepping in. A 2023 study showed that an algorithm analyzing cough sounds could tell asthma-related cough from GERD-related cough with 87% accuracy. It’s still in research, but soon, your phone might help your doctor diagnose you just by listening.Bottom line
Chronic cough isn’t a mystery. It’s a puzzle with three main pieces: UACS, asthma, and GERD. You don’t need to run every test. You need a smart, step-by-step plan. Start with the basics. Rule out meds. Try the treatments in order. Give them time. Track your symptoms. And don’t settle for “it’s just a cough.” You deserve to feel better.Can chronic cough be caused by allergies?
Yes, but indirectly. Allergies can trigger upper airway cough syndrome by causing nasal inflammation and postnasal drip. But if you have seasonal cough that matches pollen counts and improves with antihistamines, it’s likely UACS, not a direct allergy-related cough. Allergy testing isn’t usually needed unless you have other symptoms like sneezing or itchy eyes.
How long does it take to see results from a PPI trial?
It can take 4 to 8 weeks to see improvement from a high-dose PPI. That’s because the cough reflex takes time to calm down, even after stomach acid is reduced. Don’t stop the medication after two weeks if you don’t feel better yet. Stick to the full course and avoid triggers like caffeine, alcohol, and late-night meals.
Is it safe to take antihistamines long-term for chronic cough?
First-generation antihistamines like diphenhydramine can cause drowsiness, dry mouth, and constipation. They’re meant for short-term use during diagnostic trials-not lifelong. Once the diagnosis is confirmed, switching to a nasal steroid spray (like fluticasone) or saline rinses is safer for ongoing management. Long-term use of oral antihistamines isn’t recommended.
Can I have more than one cause of chronic cough at once?
Absolutely. Up to 50% of people with chronic cough have two or even all three causes-like asthma plus GERD. That’s why treatment trials are done one at a time. If you improve with one, you still need to check the others. Sometimes you need to treat all three together, especially if symptoms overlap.
Should I get a lung function test if I’ve never had asthma?
Yes. Many people with cough variant asthma have never had wheezing or been diagnosed with asthma. Spirometry is quick, non-invasive, and can detect subtle airway changes. Even if it’s normal, a methacholine challenge can still reveal hidden asthma. It’s a key part of the workup, regardless of your history.
What’s the difference between GERD and laryngopharyngeal reflux (LPR)?
GERD typically causes heartburn and regurgitation. LPR is when acid reaches the throat and voice box without causing heartburn. People with LPR often feel a lump in their throat, hoarseness, or chronic cough. It’s harder to diagnose because there’s no classic reflux symptom. That’s why the HARQ questionnaire and response to PPIs are more useful than symptoms alone.
Can stress or anxiety cause chronic cough?
Stress doesn’t cause chronic cough directly, but it can worsen it. If you already have cough hypersensitivity-common in asthma, GERD, or LPR-stress can make your nerves more reactive. That’s why some people cough more during meetings or at night when they’re overthinking. Treating the physical cause is still key, but relaxation techniques can help reduce flare-ups.
When should I see a pulmonologist?
See a pulmonologist if your cough hasn’t improved after three treatment trials, or if you have red flag symptoms like weight loss, coughing up blood, or shortness of breath. Also, if you’re being considered for newer treatments like gefapixant or camlipixant, you’ll need a specialist’s evaluation. Most cases can be handled by a primary care provider-but if the puzzle doesn’t fit, get a second set of eyes.
Chronic cough isn’t something you just have to live with. With the right approach, most people find relief within weeks. Start with the basics. Be patient. And don’t let anyone tell you it’s “just a cough.”
Melissa Taylor
December 15, 2025 AT 16:47Finally, someone breaks this down without the medical jargon overload. I’ve been coughing for 11 months and my PCP just handed me a cough syrup like it was candy. This is the guide I wish I’d found first.
Raj Kumar
December 16, 2025 AT 00:29Bro this is gold. I’m from Delhi and we’ve got this weird cough culture here-everyone’s on antibiotics like they’re candy. But yeah, ACE inhibitors? My uncle was on lisinopril for 2 years and never connected it to his cough. Switched to losartan, cough gone in 5 days. No tests needed.
Christina Bischof
December 16, 2025 AT 14:28So many people think cough = infection. I had this for 6 months, tried everything, then did the diphenhydramine + pseudo trial and boom-gone in 10 days. Turns out it was silent reflux + postnasal drip. No chest X-ray even needed. Mind blown.
Cassie Henriques
December 16, 2025 AT 17:37Just read the part about methacholine challenge. I had one last year after normal spirometry. My FEV1 dropped 15% and I was like ‘wait, I have asthma?!’ I’ve never wheezed. My doctor was shocked too. Cough variant asthma is real and underdiagnosed. Also, gefapixant sounds wild-hope it gets approved soon.
Michelle M
December 17, 2025 AT 08:17It’s funny how we’ve been trained to fear the unknown-cough for 8 weeks, panic, demand CT scans, antibiotics, nebulizers. But the truth is simpler: rule out meds, try the big three, wait. Medicine’s gotten so complex, we forget that sometimes the answer is patience and a pill, not a machine.
Sai Nguyen
December 18, 2025 AT 17:29USA medicine is broken. Why not just do the pH probe first? Waste of time with these trials. In India we just give proton pump inhibitors and move on. No testing, no delays. Why are you wasting weeks?
John Brown
December 18, 2025 AT 18:32Love how this breaks it down like a flowchart. I’m a nurse and I’ve seen so many patients get stuck in the ‘cough loop’-antibiotics → OTC meds → more antibiotics. No one ever says ‘what if it’s GERD?’ I’ll be printing this out for my clinic tomorrow.
Jocelyn Lachapelle
December 20, 2025 AT 05:50I had cough for 14 months. Tried everything. Then I stopped coffee after 6pm and didn’t eat dinner after 8. Cough cut in half in 10 days. PPIs aren’t magic, but timing matters. Also, nasal saline rinses changed my life. No pills needed.
RONALD Randolph
December 20, 2025 AT 12:54THIS is why America is falling behind. You don’t just ‘trial’ things-you diagnose with precision! Why not do the 24-hour pH probe immediately? Why waste months? This is amateur medicine. We need real diagnostics, not guesswork.
Nupur Vimal
December 20, 2025 AT 23:55Actually I think it’s all stress. I had this cough for years and I was just anxious. I stopped reading medical blogs and it went away. People make things up. You don’t need all this testing. Just chill.
Jake Sinatra
December 21, 2025 AT 16:25Thank you for emphasizing that OTC cough syrups don’t work. I used to take dextromethorphan daily. It masked the symptom but didn’t fix the cause. I finally stopped and started the PPI trial. Took 6 weeks, but now I’m cough-free. This is what real medicine looks like.
John Samuel
December 23, 2025 AT 15:03Whoa. This isn’t just a post-it’s a revolution in chronic cough management. You’ve turned a medical labyrinth into a highway. I’m not a doctor, but if I were, I’d frame this. The part about AI listening to coughs? That’s sci-fi becoming real. I’m telling my entire family to read this.
Mike Nordby
December 24, 2025 AT 13:00Correction: The term ‘postnasal drip’ is still widely used in clinical practice, even if ‘UACS’ is preferred in literature. Also, the HARQ score cutoff is 14, not 13, for optimal sensitivity. Minor point, but accuracy matters.