Chronic cough, defined as a cough lasting more than eight weeks, is a common but often vexing complaint in primary care. Guidelines from organizations like CHEST provide a structured approach, yet diagnostic journeys aren’t always straightforward. Persistent non-productive cough with a normal workup is a classic diagnostic challenge, and physicians search for a reliable differential diagnosis when standard evaluations don’t yield answers.
What happens when the initial evaluation and first-line empiric management—chest X-ray (CXR), complete blood count (CBC), spirometry and empiric proton pump inhibitor (PPI) trial for presumed gastroesophageal reflux disease (GERD)—comes back normal, but the cough persists?
The Sermo community weighed in on this exact scenario. A physician posted on Sermo about a 34-year-old man who came in with a cough that wouldn’t quit, despite the fact that all his initial tests were unremarkable. Hundreds of physicians on Sermo chimed in with their expertise, sharing what they would do next. We’ve summarized the key insights from their discussion to offer an insider perspective into the collective clinical reasoning of over 400 physicians.
Disclaimer: This article reflects the discussion and opinions of Sermo physician members on a specific, shared case. It does not constitute a diagnosis or medical advice for similar cases.
The case snapshot
Here are the details of the case as presented by the physician on Sermo:
Patient:
- 34-year-old male
- Software engineer, non-smoker, lives with a cat
- 8-week persistent, non-productive cough with occasional chest tightness
- Denies fever, chills or weight loss
- History of seasonal allergic rhinitis, intermittently treated with antihistamines
Initial workup (all normal):
- Chest X-ray (CXR)
- Complete Blood Count (CBC) with no eosinophilia
- Spirometry (pre- and post-bronchodilator)
- Proton Pump Inhibitor (PPI) trial for suspected GERD
Initial differential diagnosis:
- Post-infectious cough
- Upper Airway Cough Syndrome (UACS)
- Non-Asthmatic Eosinophilic Bronchitis (NAEB)
- Asthma with an atypical presentation
Want to see other physicians debate real cases like this? Join Sermo to participate.
Sermo consensus: the power of crowdsourced medical insights
Presented with this clinical puzzle, physicians on Sermo were polled on their next recommended step.
Nearly half (45%) of the physicians favored an empiric trial of an inhaled corticosteroid (ICS). This approach can support the possibility of NAEB or cough-variant asthma (a form of asthma where cough is the primary or sole symptom) and treat potential underlying airway inflammation, especially when referral wait times for specialized tests like a methacholine challenge can be long. As one physician noted, a trial of steroids is often the most efficient path forward: “Methacholine test is an ideal approach but can be a lengthy wait, so a trial of inhaled steroids is often a default.”
The empiric ICS trial can help differentiate NAEB or cough-variant asthma from non-inflammatory causes—something particularly useful when access to methacholine testing is limited.
Allergy testing for environmental triggers was the second most common recommendation, with 29% of votes. 14% of members supported methacholine testing as the gold standard for identifying airway hyperresponsiveness, though long wait times and limited availability can make it impractical as an initial next step. A CT scan of the chest was the least popular (12%), but remains an important tool when clinicians suspect bronchiectasis, or when the clinical course deviates from expected trajectories.
Their feedback highlights the potential of peer collaboration on Sermo. By sharing challenging cases with the community, physicians can quickly tap into the collective experience of a large, diverse group, gaining insights that can validate or refine their own clinical strategies.
Peer-to-peer debate: why allergies and inflammation dominate
The discussion among physicians largely centered on two overlapping themes: underlying allergies and airway inflammation.
The allergy/NAEB camp
Many physicians zeroed in on the patient’s history of seasonal allergic rhinitis and his cohabitation with a cat. They argued that an environmental trigger was a highly probable culprit for his persistent cough.
“Chronic sinus congestion is a frequent cause of cough—a CT scan of the sinuses is indicated,” one Sermo member writes. “Also a respiratory allergen panel is important, with an IgE level. I have seen these tests positive in spite of negative ENT evaluation, negative spirometry, and no eosinophilia.”
Another physician on Sermo likewise emphasized the likelihood of an allergic component. “I would definitely order allergy testing,” they state. “From my experience, this is a very typical presentation in someone with an environmental allergy.” A third physician advocated for proceeding with allergy testing to identify specific triggers and starting an ICS trial to provide symptomatic relief from the inflammation.
Several physicians implicitly considered non-asthmatic eosinophilic bronchitis (NAEB), describing scenarios with chronic, non-productive cough, normal spirometry, and a potential response to inhaled corticosteroids, particularly when methacholine testing was impractical. Members also noted that normal peripheral eosinophil counts do not rule out NAEB, as airway eosinophilia may still be present.
The post-nasal drip camp
Other members speculated that Upper Airway Cough Syndrome (UACS), which includes postnasal drainage and upper airway sensory hypersensitivity, was at play. Physicians noted that UACS is one of the most frequent causes of chronic cough.
“Postnasal drip is one of the most common causes, and the clinical picture is indicative of this diagnosis,” one physician writes. Recommended management for UACS often involves intranasal steroids, like Flonase, with attention to proper spray technique to ensure the medication adequately coats the nasal mucosa.
The zebras and critical exclusions
While common etiologies were front and center, the Sermo community also highlighted several “zebras”—less common but critical diagnoses that should not be overlooked when a cough persists despite a normal initial workup.
Neurogenic cough
Several physicians suggested neurogenic cough. This diagnosis of exclusion often follows an upper respiratory infection, as one physician explained. “Sounds like may be neurogenic cough! …Often happens after an URI, typically report a ‘tickle’ in the throat that precedes the cough and triggers like strong smells,” they shared. They pointed out that neuromodulators or superior laryngeal nerve blocks can reduce cough frequency in patients with neurogenic cough.
Pertussis
One Sermo member raised the possibility that this could be a case of whooping cough. “What about pertussis? We’ve seen a lot here in Mexico in adults.” While another physician argued that pertussis typically has a more extreme presentation, the original commenter countered with a personal anecdote: “Not always. I had pertussis 4 years ago…the cough was really awful especially at night but I didn’t have fever, malaise or break any ribs. It took a while to make the diagnosis because nobody thought of it.”
Anatomical or cardiac causes
A few physicians recommended looking beyond pulmonary and allergic causes if the cough remains unresolved. It was suggested that a long uvula could be an irritant: “One of the anatomical anomalies sometimes seen in Chronic Cough patients is a long uvula touching the posterior pharyngeal wall giving irresistible cough.”
While it’s rare, chronic cough can occasionally be a manifestation of underlying cardiac pathology, even when pulmonary evaluation is normal. Conditions such as heart failure can cause pulmonary congestion and airway irritation, leading to a persistent cough—often described as worse at night or when lying flat. Although this patient had no cardiac symptoms on exam, multiple Sermo members recommended a cardiac workup as a next-step exclusion strategy once the more common pulmonary and allergic etiologies have been ruled out.
Persistence is key
The Sermo commentary on this challenging case underscores that even with advanced diagnostics, clinical reasoning remains paramount. The majority of physicians pointed toward a practical, layered approach: start with likely causes, treat empirically and be prepared to dig deeper if the patient doesn’t improve.
Solving diagnostic dilemmas often requires collaboration. Communities like Sermo provide a space for physicians to lend their expertise, learn from their peers and ultimately improve patient outcomes. In fact, the physician who posted this case was able to mark it as solved thanks to the contributions and insights shared by their peers.
Want to contribute your thoughts to the next challenging case? Join Sermo to connect with more than 1 million of your peers.
